Repaint PDF highlights by row, send rasters by shared memory, and animate messages

PDF highlights (hover preview, search, selection) are baked into page rasters,
and any change re-rendered the whole page with MuPDF; the TTY then re-sent it
as base64 (4.7 MB a page), the GUI as a new texture. Worse, a pointer motion
over a PDF invalidated the page even when no preview was shown, so every
motion paid that. Now:

- A raster whose baked highlight set equals the wanted one is left alone.
- A highlighted page keeps its clean rows (before highlights and tint); a
  change repaints only the rows of quads that differ, running MuPDF's
  highlight pass (pardes_pdf_paint_highlights) over those clean rows and
  tinting them: the operations a full render performs, so the pixels are
  identical. MuPDF band renders are NOT bit-identical to a whole page (edge
  rows, resampled images), so they are never used to patch; the comment
  claiming otherwise is corrected.
- ImagePlace.patch hands shells the changed rows; the GUI uploads just those
  rows into the texture it holds.
- The TTY probes kitty shared memory (t=s) with an id vaxis never reaches and
  sends rasters as a /dev/shm name when the terminal reads it; direct base64
  otherwise (ssh).
- Shells that take row patches (GUI, TTY with shm) repaint a selection while
  it is dragged instead of only on release.

Latency elsewhere:
- TTY: an animating frame no longer sleeps 16 ms blind; a tick thread posts
  into the input queue, so input inside the frame is handled at once.
- TTY and GUI: queued pointer motions coalesce to the last.
- GUI: a skipped swapchain image re-arms the frame (3 retries); animations
  still tick while nothing presents.
- Editing: the line index is carried across an edit instead of rebuilt from
  a scan of the whole file per keystroke.

Messages fall into their row (ease-in; the GUI slides the band out from under
the tagline, a terminal fades it), stay until the next input as before, linger
MessageLinger ms (default 800), and dissolve (ease-out). MessageAnimation
toggles it; both are settings, in Config and startup files. The snapshot
harness pins the old behaviour. The detached server now ticks animations.

A restored terminal comes back live: the old screen and scrollback (dumped
as clean VT by ghostty's formatter, replayed at the new size; older dumps
fall back to their rendered text), a dim
"restored history" marker, then a new shell in the directory it was in.

Right-click on a line number in a file pane looks at that line (a sticky
context header's number included).

Measured with an external pty driver (TTY), an in-process fence trace
(GUI, PARDES_TEST_LATENCY), and test/pdf_pointer_bench.zig (pixel identity
against the baseline and a whole-page oracle); balanced A/A/B rounds, paired
per-round statistics.

Messages stack: each event gets its own row and its own fall, linger and
dissolve; a line keeps its row until it leaves and a new one fills the first
free row. Announcements and statuses are replaced in place, not stacked.
MessageFall, MessageDissolve and DumpDir are settings Config reports.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

4 files changed, 19 insertions, 12 deletions

diff --git a/test/snapshots/builtins.snap b/test/snapshots/builtins.snap
index cd47209f..02547b91 100644
--- a/test/snapshots/builtins.snap
+++ b/test/snapshots/builtins.snap
@@ -19,6 +19,10 @@ wheel up 110 50
 wheel up 110 50
 wheel up 110 50
 wheel up 110 50
+wheel up 110 50
+wheel up 110 50
+wheel up 110 50
+wheel up 110 50
 wait 10000 Look                  enter, right-click
 wait 10000 Exec                  tab, middle-click
 wait 10000 Filter
diff --git a/test/snapshots/dump.golden b/test/snapshots/dump.golden
index 8f920136..e466dbf1 100644
--- a/test/snapshots/dump.golden
+++ b/test/snapshots/dump.golden
@@ -38,6 +38,7 @@
                 .cwd = "/tmp/pardes-snap/dump/cwd",
                 .stream = "ls\nd.txt\n",
                 .stream_b64 = <elided>
+                .stream_is_screen = true,
                 .cursor = .{ .col = 2, .row = 2 },
             },
             .file = null,
@@ -57,6 +58,7 @@
                 .cwd = "/tmp/pardes-snap/dump/cwd",
                 .stream = "ls\nd.txt\n",
                 .stream_b64 = <elided>
+                .stream_is_screen = true,
                 .cursor = .{ .col = 2, .row = 2 },
             },
             .file = null,
@@ -76,6 +78,7 @@
                 .cwd = "/tmp/pardes-snap/dump/cwd",
                 .stream = "ls\nd.txt\n",
                 .stream_b64 = <elided>
+                .stream_is_screen = true,
                 .cursor = .{ .col = 2, .row = 2 },
             },
             .file = null,
diff --git a/test/snapshots/load.golden b/test/snapshots/load.golden
index 994ab83e..32024cec 100644
--- a/test/snapshots/load.golden
+++ b/test/snapshots/load.golden
@@ -2,10 +2,10 @@
 |Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Kill
 |   New Tty Find Grep Joincol Delcol                  New Tty Find Grep Joincol Delcol
 |   /tmp/pardes-snap/load/cwd Tty Save Mode Filter    /tmp/pardes-snap/load/cwd Tty Save Mode Filter
-|  echo LOAD''MARK; seq 1 40; echo E''ND             ls
+|  $ echo LOAD''MARK; seq 1 40; echo E''ND           $ ls
 |  LOADMARK                                          d.txt
-|  1
-|  2
+|  1                                                 $
+|  2                                                 ── restored history ──
 |  3
 |  4
 |  5
@@ -17,8 +17,10 @@
 |  11
 |  12
 |   /tmp/pardes-snap/load/cwd Tty Save Mode Filter
-|  ls
+|  $ ls
 |  d.txt
+|  $
+|  ── restored history ──
 == style loaded grid=100x31
 |0: 0-70 #b2c3b8,#1d2824, 71-99 d,#1d2824,
 |1: 0-1 #ffffff,#887455, 2-2 d,#26362d, 3-34 #becfc4,#26362d, 35-49 d,#26362d, 50-51 #ffffff,#887455, 52-52 d,#1d2824, 53-84 #b2c3b8,#1d2824, 85-99 d,#1d2824,
@@ -26,8 +28,8 @@
 |3: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |4: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |5: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
-|6: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
-|7: 0-0 d,#152019, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
+|6: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-73 #e5eee5,#0d1410,f 74-99 #e5eee5,#0d1410,
+|7: 0-0 d,#152019, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-99 d,#0d1410,
 |8: 0-0 d,#152019, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |9: 0-0 d,#152019, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |10: 0-0 d,#152019, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
@@ -41,8 +43,8 @@
 |18: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |19: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |20: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
-|21: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
-|22: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
+|21: 0-0 d,#608269, 1-1 d,#0d1410, 2-23 #e5eee5,#0d1410,f 24-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
+|22: 0-0 d,#608269, 1-49 d,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |23: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |24: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
 |25: 0-0 d,#608269, 1-1 d,#0d1410, 2-49 #e5eee5,#0d1410, 50-50 d,#608269, 51-51 d,#0d1410, 52-99 #e5eee5,#0d1410,
diff --git a/test/snapshots/restore.golden b/test/snapshots/restore.golden
index 11d92288..01b52984 100644
--- a/test/snapshots/restore.golden
+++ b/test/snapshots/restore.golden
@@ -6,9 +6,7 @@
 |  $ echo KEEP''ME
 |  KEEPME
 |  $
-== snap restored grid=100x31 cursor=4,6
+== snap restored grid=100x31 cursor=4,8
 |0: Newcol Joincol Find Grep Help Changelog Tutor Dump NextColor Debug Kill
 |2:    /tmp/pardes-snap/restore/cwd Tty Save Mode Filter Collapse Del
-|3:   ls
-|4:   echo KEEP''ME
-|6:
+|7:   ── restored history ──