One Layer for tags, notices, headers and bodies; a taller tag is one layer of rows; wire v8

src/Layer.zig merges TagLayer and BodyLayer. `rows` (0 = no layer) and a
cursor at {x, y}. A tag of N rows is ONE layer of N grid rows: tagHit answers
the row as `line`, bodyHit keeps its meaning, and the per-line layer bases
(TAG_LINE_LAYER_BASE, HEADER_LINE_LAYER_BASE) are gone, not aliased.

Wire v8, the one bump: tag layers carry rows and cursor y, and the frame
carries the placed region list. v7 and v9 peers are refused in both
directions (server test over both, a new frontend test over both).

web: tag_layer_value 11 = rows, 12 = cursor y; app.mjs lays every row.
macOS: the Zig side compiles against Layer; pardes.h still sees one row
per tag layer (accepted, the macOS shell is ignored for now).

No visual change: snapshot goldens and the 17 GUI goldens byte-identical.

Shared files touched: pardes.zig, Messages.zig, gui.zig, macos.zig,
detached/client.zig, detached/server.zig, detached/wire.zig (plus web.zig,
app.mjs, edit.zig, look.zig). Not touched: mouse.zig, tagline.zig,
colors.zig, tty.zig, dump.zig, exec.zig, host_io.zig, panes.zig.

1 files changed, 1 insertions, 1 deletions

diff --git a/docs/render-pipeline.md b/docs/render-pipeline.md
index f63b9a0b..a8b3f019 100644
--- a/docs/render-pipeline.md
+++ b/docs/render-pipeline.md
@@ -809,7 +809,7 @@ stripped. No visual change until stage 9 unless stated.
 | 4 | PLACE: Region list built once; renderPane/tags/notices read their rects from it | wait for tag→Text; the refactor is already replacing BOX_H with `pane.tag_rows` and `p.tagTop/bodyTop(pane, r)` — PLACE absorbs those into the region rects |
 | 5 | JOIN: paint tags/notices/headers once into layers, copy into grid; the grid wins where the copies disagree, and each disagreement is listed for a later decision | goldens are the oracle; wide-grapheme re-clip at the edge (§3.2) |
 | 6 | body layer joined the same way (paint once, copy visible rows) | riskiest join; A/B the old double paint in a temporary test with tag_bottom on and off, then delete it |
-| 7 | Layer merge (TagLayer + BodyLayer), wire v8, web accessors | after the other agent lands; touches mouse hit paths; breaks the macOS shell's layer ABI (accepted: macOS build ignored for now) |
+| 7 | Layer merge (TagLayer + BodyLayer), wire v8, web accessors | after the other agent lands; touches mouse hit paths; breaks the macOS shell's layer ABI (accepted: macOS build ignored for now); done: one `Layer` (src/Layer.zig) with `rows` (0 = no layer) and a `cursor{x, y}`; a tag of N rows is ONE layer of N grid rows (`tagHit` answers the row as `line`, `bodyHit` keeps its meaning), so the per-line layer bases are gone. Wire v8 ships rows, cursor y and the region list in the one bump; v7 and v9 peers are refused in both directions (tests). web: `tag_layer_value` 11 = rows, 12 = cursor y, and app.mjs lays every row. macOS: its Zig side compiles against `Layer`, but pardes.h still sees one row per tag layer (a taller tag shows its first row there) |
 | 8 | GUI draws from regions: role tiers with track groups in tiers 2-3, page cover, hard-edged snapped decor for rules/rails/grips (pane chrome in the pane's tier), per-instance clip; delete inference functions, `transient_on` and `mark_hover` (breaks macOS glass hover; accepted, macOS ignored for now) | stage-0 PPM goldens byte-identical (possible only because hard decor is snapped and not anti-aliased); pane chrome now also shows during transitions, which is the one allowed visible delta, listed |
 | 9 | post chain: glslang, Shadertoy prefix, ping-pong, ShaderAnimation, redraw levels A/B (§5.5); bundled CRT without barrel; delete scene_effects/crt.zig/crt.frag | first visual change (the CRT look) |
 | 10+ | `fx` bookmark: G1–G3 → feel review → G4 bundled → G5 lapis theme → P2s; tty T1–T2 → feel review → removals of audited effects (after user decision) → T3–T5 | each effect its own change, default off |