First Phase B session: pmacs-gpu can move its own cursor. Consumer-only
(the daemon already dispatches FrontendEvent::Key through the same
keymap/command stack the TUI uses; verified in the Phase B framing).
- `AttachClient::send_key` emits `FrontendEvent::Key`.
- `translate_key` maps winit logical key + modifier state → protocol
(Key, Modifiers). Covers the full editing set; `is_motion_key` gates
B1 to cursor-motion keys only (arrows, Home/End, PageUp/PageDown) so
no buffer mutation happens yet — editing keys open in B2 by dropping
the gate. Modifiers tracked via winit `ModifiersChanged`.
- `window_event` rework: Escape stays a local quit; other pressed keys
translate and (motion-gated) `send_key`.
- Consume `InstanceMessage::CursorByte` → `own_cursor` (Q#B3: the
daemon is authoritative; the caret follows whatever it reports, incl.
command-driven motion this frontend never interprets).
- Caret: a thin quad bar drawn *over* the text at the cursor glyph,
byte→glyph mapping rebased per line via `line_byte_offsets[line_i]`
(bet B4 / the QB3 lesson applied up front).
- Un-suppress own-window `Selection`/`CurrentLine` washes from
`current_decorations` alongside peer presence (Q#B4): the QB1
suppression lifts now that the own cursor is live. The bg-wash
builder split into `collect_own_decoration_rects` +
`collect_peer_rects`.
- own_cursor cleared on BufferSnapshot (prior-buffer offsets).
Tests: `translate_key_maps_motion_named_keys_and_chars`,
`translate_key_carries_modifiers`. pmacs-gpu unit 18 (+2).
Gates green: fmt; clippy --all-targets --workspace -D warnings (default
+ crdt); pmacs-gpu unit 18. Daemon/lib untouched.
NOT YET VISUALLY VALIDATED — per the Phase B framing's process
correction, this must be confirmed in a running pmacs-gpu (arrow keys
move the caret + own current-line wash; TUI unaffected) before merge.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth
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