clipboard, n/N and the tty prompt: three things that were half-wired

Three changes that all turned out to be the same shape -- a feature that
worked in one direction, or for one pane kind, and quietly did not in the
others.

CLIPBOARD. Every register write emitted set_clipboard, so deleting one
character threw away whatever the desktop was holding; multi-cursor yank took
the join's early return and emitted nothing at all, so the same key reached
the clipboard on one cursor and not on two. Nothing could READ the clipboard:
the SDL shell had no SDL_GetClipboardText anywhere in it, and the tty shell
never asked for OSC 52, so `p` from another application was dead in both.

Now it is helix's split. y/d/c/p/P/R and the acme chords are the DEFAULT
REGISTER and nothing else; the system clipboard is five words on helix's own
letters -- SPC y, SPC Y, SPC p, SPC P, SPC R -- spelled as builtins so they
land in Help and are executable like every other verb. The one exception is
the tag `y` chord, which still mirrors out because a tag is always insert, so
SPC cannot be pressed there, and copying the path out is the whole point of
the chord.

Reading is a new read_clipboard effect answered by an ordinary Event.paste, so
the round trip is honest about being one: SDL and NSPasteboard answer inside
the same drain, the browser answers a promise, and a terminal answers over
OSC 52 or -- far more often -- refuses. A refused read is a paste that does
not happen, and the request dies at the next keystroke rather than landing
minutes late in whatever pane is focused by then.

The tty shell also enables BRACKETED PASTE now and coalesces
paste_start..paste_end into one event. Before this a paste arrived as a flood
of individual key presses: plausible in insert mode, and in normal mode every
pasted character ran as a command.

n/N. They stepped the armed results buffer and immediately Looked each row, so
you could not walk past a hit without opening it. They are a MOTION now:
select the next look-able text, open nothing, and let Enter decide. What they
step is the largest whitespace-delimited run look.resolve can act on
(look.lookableSpan, wrapper punctuation peeled), over a RING of panes -- every
pane that has performed a look, most recent first, then the output buffers
that have not, newest first, and only if both are empty the pane in front of
you. N is the exact inverse of n, computed rather than remembered: both
directions ask the same question about the same spans and compare against the
column the walk parks on, so x presses one way and x back land exactly where
you started, pane boundaries and the ring's seam included.

A ring rather than a list with two ends because a shell's cursor sits at the
prompt, below everything it has printed, so a walk that could not come round
would have nowhere to go on the very first press -- which is the case n/N were
written for.

One motion everywhere, no pane-kind or buffer-kind special case. The only
thing a buffer may change is the GRAIN of what a step selects, and it does it
with one flag rather than a branch: output_pane.Traits.commands (renamed from
`executes`, which named one reader's behaviour rather than the fact) makes a
row select WHOLE, because a ThemeSel line is a word to run and has no path
inside it to pick out. `]d`/`[d` are not n/N -- they are helix's diagnostic
motions, their job is to ARRIVE, and they still reach searchStep.

THE TTY PROMPT. Leaving raw tty blanked the prompt row, and the command you
had typed at that prompt shares the row, so it went too -- a shell out of tty
read as output only. OSC 133 marks the row CELL by cell, so the two are
separable: config.tty_blank = .prompt cuts the prompt's own columns and leaves
the command, left-hugged at column 0 in line with the output under it rather
than in a bay of blanks. .prompt_and_input is the old behaviour, kept.

Because the row is now something you can put a cursor in, enterTty adds the
hidden prompt width back before asking ghostty to walk the shell's own cursor
to it -- the modal column on a cut row is short by exactly that much.

Verified: unit-test 186/186 (nine new), snap 87/87 (new ttyprompt.snap),
hxdiff 481 and hxparity 561 with 0 mismatches, tty and gui both build. And
against the real binaries rather than the harness: in a pty, SPC y emits OSC
52 carrying exactly the selection while plain y emits nothing, SPC p issues
the read and pastes the reply, and a bracketed paste of "dd..." inserts text
instead of deleting two lines. In a real SDL window, SPC y then SPC p round
trips through the system clipboard while the default register holds different
text. Setting tty_blank back to .prompt_and_input reproduces all 86 old
goldens byte for byte.

1 files changed, 18 insertions, 13 deletions

diff --git a/docs/helix-keys.md b/docs/helix-keys.md
index e43bc6b4..214a1280 100644
--- a/docs/helix-keys.md
+++ b/docs/helix-keys.md
@@ -29,8 +29,8 @@ layer: gap offsets + ranges over the flat text). Differential harness:
   collapse) — the checked-in helix goldens are the ground truth, verified
   case-by-case by `zig build hxdiff`. Motion-created ranges live in
   `pane.vsel` marked IMPLICIT (`vsel.explicit = false`); `v` extend mode,
-  `x`/`X`, terminal `n`/`N` (lookStep) and file `n`/`N` (searchStep) set
-  EXPLICIT ones. `d`/`c`/`y`/`~`/… act on the active selection either
+  `x`/`X` and `n`/`N` (the look-ring walk, `lookWalk`) set EXPLICIT ones.
+  `d`/`c`/`y`/`~`/… act on the active selection either
   way — that is the point of the model. The pardes-specific chords
   (normal-mode Enter look / Tab execute)
   act on EXPLICIT selections only and fall back to the word under the
@@ -55,7 +55,10 @@ Parity column (phase 5): **helix-verified** = matched field-by-field
 (text/mode/cursor/anchor) against the helix goldens by `zig build hxdiff`;
 **pardes-specific** = key helix leaves unbound (or a deliberate pardes
 binding) — cannot mismatch a golden; **waived** = corpus-covered divergence
-with a reason in `test/hxcases/waivers.jsonl`.
+with a reason in `test/hxcases/waivers.jsonl`; **out of corpus** = helix's
+own key and meaning, but the work leaves the core as an EFFECT the headless
+differential has no shell to perform — the clipboard commands, and nothing
+else.
 
 | Key | Behavior (pardes today) | Notes / quirks vs helix | Parity |
 | --- | --- | --- | --- |
@@ -80,9 +83,9 @@ with a reason in `test/hxcases/waivers.jsonl`.
 | `x` / `<n>x` | select current line / extend one (n) line(s) down, char-range through the newline, cursor ON the `\n` | col-0 vim-ism removed (phase 5); matches `extend_line_below`, mode stays normal | helix-verified |
 | `d` | delete selection (implicit or explicit); bare cursor = the 1-wide selection | always yanks (`Alt-d` noyank in B); terminals: drops typed runs only | helix-verified |
 | `c` | change (delete + insert mode); linewise selections open a fresh indented line | same shape as `d` | helix-verified |
-| `y` | yank selection; bare cursor yanks the 1-wide selection (char under cursor) | line-yank vim-ism removed (phase 5); yank keeps selection AND cursor (helix). Also emits `set_clipboard` (OSC 52 out) | helix-verified |
+| `y` | yank selection; bare cursor yanks the 1-wide selection (char under cursor) | line-yank vim-ism removed (phase 5); yank keeps selection AND cursor (helix). Writes the DEFAULT REGISTER and nothing else — the system clipboard is `SPC y`, which is helix's own split and so moves this row TOWARDS helix, not away: a `d` of one character can no longer clobber what the desktop was holding | helix-verified |
 | `u` / `U` | undo / redo | restores the pre-edit selection (helix); snapshot granularity, no `Alt-u`/`Alt-U` history walking (skipped) | helix-verified |
-| `p` (normal) | paste the core's yank register after the selection | helix default-register semantics; yank still mirrors OUT via OSC 52 (`set_clipboard`) but `p` never reads the system clipboard back — most terminals refuse the OSC 52 read, which left `p` a silent no-op | helix-verified |
+| `p` (normal) | paste the core's yank register after the selection | helix default-register semantics, and only the register — nothing on this path reads or writes the system clipboard. `SPC p` is the word that does, and on a tty its read is OSC 52, which most terminals refuse: an honest no-op there rather than a paste of the wrong text | helix-verified |
 | `Esc` (body normal) | clear a pending modal prefix / exit select mode, keeping the selection, then run `Last`: hop to the pane you were in before this one, whichever kind it was, exactly like `SPC j j` — so held down it alternates between two panes, two files as readily as a file and its shell | Pardes-specific focus binding layered on helix's cleanup. A leader path, tag, topbar or search owns Esc while it is active; raw tty forwards it | pardes-specific (cleanup helix-verified) |
 | `Esc` (insert) | back to normal mode, cursor right after the insertion (no vim left-step) | | helix-verified |
 | `Enter` (normal) | acme **look** chord: EXPLICIT selection, else file-ish word under cursor | pardes-specific, keep (helix normal-mode Enter unbound). Covers helix `gf`. Implicit motion residue falls back to the cursor word | pardes-specific |
@@ -92,9 +95,11 @@ with a reason in `test/hxcases/waivers.jsonl`.
 | `Ctrl-w` + `h/j/k/l`/arrows | directional pane focus prefix — normal/tty modes only | pardes' own window handling (helix window mode skipped, section C). Runs the SAME `Left`/`Down`/`Up`/`Right` builtins `SPC w h/j/k/l` runs; kept alongside the leader because a pane in raw **tty** mode never sees `SPC` (the shell owns it), so this is the only keyboard way out of one. Insert mode owns `Ctrl-w` = delete-word-back, so a tag being TYPED into swallows it; from a tag in normal mode (`:`) it moves focus to the neighbour's BODY, while the bare letters `h/j/k/l` there move to its TAGLINE (next row) | pardes-specific |
 | `Alt-n` | new terminal below (any mode) | shadows helix `Alt-n` TS sibling-select — skipped anyway (tree-sitter) | pardes-specific |
 | `Alt-c` | move active terminal to a fresh column (any mode) | helix `Alt-c` is change-noyank; the pardes window op wins (do-not-touch contract). `Alt-d` + `i` covers the behavior | waived (`alt-c-window-op`) |
-| `Space` (normal, body) | the pardes LEADER: a key path from here runs a BUILTIN with no arguments — the same builtins the topbar and the tags hold. `SPC k` Kill, `SPC d` Del, `SPC f s` Save, `SPC f n` New (an empty temporary file focused in the calling pane's column), `SPC f f` Find (fd over the pane's directory, results into `+Search`), `SPC f g` Grep (grep -R over the CONTENTS of every pane's directory, the ones another pane already covers dropped, rows relative to the asking pane's own directory, results into `+Search`; like Find it takes an ARGUMENT — `Grep foo` executed, or a selection chorded onto the word, searches that and skips the input), `SPC h t` Tutor, `SPC c n`/`SPC c d` Newcol/Delcol, `SPC t d/c/n/r` Debug/Colors/NextColor/Crt, `SPC t t` ThemeSel (the whole theme ring as `Theme <name>` rows in an output buffer — the one list whose rows are COMMANDS, so n/N execute each row instead of looking it and stepping is a live preview), `SPC t p/l/a` Petscii/Palette/Ascii (an image pane's renderer toggles — the words its tag used to spell out, so the bar stays a bar), `SPC s d`/`SPC s r` Dump/Restore, `SPC w h/j/k/l` Left/Down/Up/Right (directional pane focus — the `Ctrl-w` prefix's four moves as builtins), `SPC j o`/`SPC j i`/`SPC j j`/`SPC j l` Back/Forward/Last/Jumplist (the jump stack: walk it back, walk it forward, hop to the pane before this one — what body-normal Esc runs — and read the stack as a clickable buffer). `?` at ANY depth opens the Help builtin listing what the prefix can still reach (`SPC ?` = all, `SPC h ?` = the docs group), into a `+Help` output buffer. The pending path shows at the right edge of the active pane's tag; Esc — or any unmapped key — abandons it | helix spends Space on pickers/LSP (section C); pardes has neither, and acme's builtins are what a leader is for. Enum-derived: the paths, the Help lines and the execute dispatch all fold out of one `Builtin` enum at comptime. Normal mode on a BODY only — tags are always insert, tty keys belong to the program | pardes-specific |
-| `/` then `n`/`N` (any pane) | pardes' own plain-substring search into a `+Search` output buffer, n/N walk the result rows and look them (EXPLICIT selections) | KEEP, do not touch; not in the corpus (helix `/` is regex search) | pardes-specific |
-| `n`/`N` (terminal panes, no search armed) | lookable-token motion over scrollback (EXPLICIT selections) | KEEP, do not touch | pardes-specific |
+| `Space` (normal, body) | the pardes LEADER: a key path from here runs a BUILTIN with no arguments — the same builtins the topbar and the tags hold. `SPC k` Kill, `SPC d` Del, `SPC f s` Save, `SPC f n` New (an empty temporary file focused in the calling pane's column), `SPC f f` Find (fd over the pane's directory, results into `+Search`), `SPC f g` Grep (grep -R over the CONTENTS of every pane's directory, the ones another pane already covers dropped, rows relative to the asking pane's own directory, results into `+Search`; like Find it takes an ARGUMENT — `Grep foo` executed, or a selection chorded onto the word, searches that and skips the input), `SPC h t` Tutor, `SPC c n`/`SPC c d` Newcol/Delcol, `SPC y/Y/p/P/R` the five clipboard words (next row), `SPC t d/c/n/r` Debug/Colors/NextColor/Crt, `SPC t t` ThemeSel (the whole theme ring as `Theme <name>` rows in an output buffer — rows that are COMMANDS rather than places, so a theme is previewed by EXECUTING one, Tab or a middle click; `n`/`N` do not run them, they step past to the next look-able text on the ring), `SPC t p/l/a` Petscii/Palette/Ascii (an image pane's renderer toggles — the words its tag used to spell out, so the bar stays a bar), `SPC s d`/`SPC s r` Dump/Restore, `SPC w h/j/k/l` Left/Down/Up/Right (directional pane focus — the `Ctrl-w` prefix's four moves as builtins), `SPC j o`/`SPC j i`/`SPC j j`/`SPC j l` Back/Forward/Last/Jumplist (the jump stack: walk it back, walk it forward, hop to the pane before this one — what body-normal Esc runs — and read the stack as a clickable buffer). `?` at ANY depth opens the Help builtin listing what the prefix can still reach (`SPC ?` = all, `SPC h ?` = the docs group), into a `+Help` output buffer. The pending path shows at the right edge of the active pane's tag; Esc — or any unmapped key — abandons it | helix spends Space on pickers/LSP (section C); pardes has neither, and acme's builtins are what a leader is for. Enum-derived: the paths, the Help lines and the execute dispatch all fold out of one `Builtin` enum at comptime. Normal mode on a BODY only — tags are always insert, tty keys belong to the program | pardes-specific |
+| `SPC y` `SPC Y` `SPC p` `SPC P` `SPC R` | helix's clipboard menu on helix's own letters: yank the selection to the system clipboard (`ClipYank`) or the PRIMARY selection alone (`ClipYankMain`), paste the system clipboard after (`ClipPaste`) / before (`ClipPasteBefore`) the selection, replace the selection with it (`ClipReplace`) | the ONLY five words in pardes that touch the desktop's clipboard — `y`/`d`/`c`/`p`/`P`/`R` and the acme cut/paste chords are the internal register alone. Builtins rather than bare chords because a leader path names a builtin: they land in Help's index and are executable words like every other verb. One divergence: pardes keeps a single register VALUE where helix keeps one per range, so `SPC y` at N cursors joins them with newlines (`Pardes.setYank`, the divergence `msel-yank-paste` already waives). On a tty the write is OSC 52 out and the READ is OSC 52 back, which many terminals refuse or gate — so `SPC y` works there and `SPC p` can be a no-op | out of corpus |
+| a paste from the OUTER terminal | one `Event.paste`, spliced in at the cursor | the tty shell enables bracketed paste and coalesces `paste_start`..`paste_end` into a single event; before that the bytes arrived as individual key presses and normal mode RAN them, which is how a pasted `d` deleted a line. The bytes deliberately never enter the yank register — clipboard and default register are separate stores in both directions | pardes-specific |
+| `/` (any pane) | pardes' own plain-substring search into a `+Search` output buffer: the tag takes the pattern, Enter fills the buffer, and its rows are ordinary look targets | KEEP, do not touch; not in the corpus (helix `/` is regex search). The stepping half is the next row | pardes-specific |
+| `n` / `N` (any pane) | MOTION, not a jump: move the SELECTION to the next / previous look-able text and open NOTHING. Enter — the look chord — on what it leaves selected is what opens it | KEEP, do not touch; not in the corpus (helix's `n`/`N` walk regex search hits). The text stepped is the largest whitespace-delimited run `look.resolve` can act on (`look.lookableSpan`, wrapper punctuation peeled off both ends), and the walk is a RING across PANES: every pane that has performed a Look, most recent first (`Pardes.look_src`), then the output buffers that have not, newest first, and only when both are empty the active pane. Exhausting a pane enters the next at its first (forward) / last (backward) span and the end wraps to the start, so `N` is the exact inverse of `n`. What it lands on becomes an EXPLICIT `vsel` with the cursor on its FIRST column, in the pane the walk focuses. ONE motion in every pane kind and every buffer kind — a PDF steps the `+Search` buffer its own search filled, `n` to select the row and Enter to jump. The single thing a buffer may change is the GRAIN of what a step selects, and it changes it with one flag rather than a branch: `output_pane.Traits.commands` makes a step take the WHOLE LINE, because a command list (`ThemeSel`/`FontSel`) holds words to run and there is no path inside `Theme gruvbox` to pick out. Tab on what `n` selected wears the theme, which is the same middle click on the row is. `]d`/`[d` are helix's diagnostic motions, a different binding, and they do still jump to each diagnostic (`docs/lsp.md`) | pardes-specific |
 | insert: printable text | file: real edit; terminal: typed run splice | | helix-verified (file) |
 | insert: `Enter` | newline; keeps the current full indent levels and adds one 4-space logical tab when the text before the cursor ends in `(`, `[`, `{`, or `)` (including `})`) | plain lines match `insert_newline`; delimiter heuristic is pardes-specific | helix-verified (plain) / pardes-specific (delimiter) |
 | insert: `Backspace` (+ `Shift-Backspace`) | delete prev char, joins lines at col 0 | matches `delete_char_backward`; `Ctrl-h` alias in B | helix-verified |
@@ -139,7 +144,7 @@ Phase 2 state added to `Pane`: `count` (accumulator, capped 0xffff),
 | Key | Behavior | Notes | Status |
 | --- | --- | --- | --- |
 | `r<ch>` | replace selection/char with `<ch>`, newlines kept | terminals: replaces the typed-run byte under the cursor if any, else no-op (`runByteAt`) | helix-verified (phase 5) |
-| `R` | replace selection (or cursor char) with the yank register; pasted text becomes the selection, head on its last char | uses the INTERNAL yank (`p.yank`), no clipboard round trip; empty register = no-op; terminals: no-op | helix-verified (phase 5) |
+| `R` | replace selection (or cursor char) with the yank register; pasted text becomes the selection, head on its last char | uses the INTERNAL yank (`p.yank`), no clipboard round trip — `SPC R` is the system-clipboard twin; empty register = no-op; terminals: no-op | helix-verified (phase 5) |
 | `~` | switch case of selection/char, selection kept | terminals: run byte only | helix-verified (phase 5) |
 | `` ` `` | selection to lowercase | terminals: run byte only | helix-verified (phase 5) |
 | ``Alt-` `` | selection to uppercase | terminals: run byte only | helix-verified (phase 5) |
@@ -276,8 +281,8 @@ text.
 
 | Key(s) | Helix behavior | Reason |
 | --- | --- | --- |
-| `?`, `*`, `Alt-*` | rsearch / selection-as-pattern | search — pardes has its own `/` n N (plain substring into an output buffer, kept as-is); helix regex search machinery not wanted |
-| `Space` mode, all rows (`f F e . b j g G k s S d D r a h ' w c C Alt-c p P y Y R / ?`) | pickers, LSP actions, clipboard menu, global search, palette | helix's space mode is pickers + LSP + a clipboard menu, none of which exist here — but the KEY is taken: pardes' own leader runs the acme builtins (section A). Clipboard: yank mirrors out via OSC 52, `p` pastes the register |
+| `?`, `*`, `Alt-*` | rsearch / selection-as-pattern | search — pardes has its own `/` (plain substring into an output buffer, kept as-is) and an `n`/`N` that SELECTS the next look-able text instead of walking match hits; helix regex search machinery not wanted |
+| `Space` mode, all rows but the clipboard menu (`f F e . b j g G k s S d D r a h ' w c C Alt-c / ?`) | pickers, LSP actions, global search, palette | helix's space mode is pickers + LSP, neither of which exists here — but the KEY is taken: pardes' own leader runs the acme builtins (section A). The clipboard menu is the half that DOES exist now: `<space>y Y p P R`, helix's letters on helix's leader, in section A |
 | Popup `Ctrl-u`/`Ctrl-d`, Completion menu, Signature help tables | LSP popups | LSP |
 | Picker table (all rows), Prompt table (all rows) | picker / prompt internals | pickers — pardes' tag line is its own one-line editor |
 | `gn` `gp` `ga` `gm` | next/prev/alternate buffer | buffer nav — pardes panes aren't a buffer list |
@@ -288,7 +293,7 @@ text.
 | `]f [f ]t [t ]a [a ]c [c ]e [e ]T [T ]x [x` | TS unimpaired jumps | tree-sitter |
 | `]g [g ]G [G` | git change jumps | needs VCS diff state |
 | `gd gD gy gr gi`, `=`, `]d [d ]D [D`, insert `Ctrl-x` | definition/refs/format/diagnostics/completion | LSP |
-| `"` `<reg>`, insert `Ctrl-r` | register select / insert | registers — single yank register only |
+| `"` `<reg>`, insert `Ctrl-r` | register select / insert | registers — one yank register and no way to name a second; the system clipboard is not spelled as a register here either, it is the five `SPC` commands in A |
 | `Q` / `q` | record / replay macro | macros — needs replayable input log |
 | `Ctrl-i` `Ctrl-o` `Ctrl-s` (normal) | jumplist forward/back/save | jumplist |
 | `Alt-u` / `Alt-U` | undo-history earlier/later | history timeline — linear snapshot u/U covers pardes |
@@ -304,7 +309,7 @@ text.
 | `Z` (sticky view mode) | persistent view mode | marginal; `z` one-shots suffice |
 | `zm` (view) | align middle horizontally | marginal even with hscroll |
 | `.` | repeat last insert | **deferred by decision**: needs recording the insert session's keystrokes and a replay path — a new subsystem; undo is whole-buffer snapshots with no edit log to piggyback on. Revisit after phases 2–5 if the log exists by then for another reason |
-| Select/extend mode section (prose) | `v` turns all motions into extenders, `n`/`N` keep selections | implemented for motions (phase 5: `pane.select` + the fixed anchor, differential-verified — see the `v` row in A); helix's search-`n`/`N` extension doesn't apply (pardes `n`/`N` are its own search/look ops) |
+| Select/extend mode section (prose) | `v` turns all motions into extenders, `n`/`N` keep selections | implemented for motions (phase 5: `pane.select` + the fixed anchor, differential-verified — see the `v` row in A); helix's search-`n`/`N` extension doesn't apply (pardes' `n`/`N` is the look-ring motion, which REPLACES the selection with the span it lands on) |
 
 ## Differential testing (phase 5)