fix(shortcuts): Ctrl+W no longer closes a session

Close Session was bound to Ctrl+W by default. Ctrl+W is delete-word in
every shell, readline prompt and agent CLI, so muscle memory killed the
session (its tmux pane and CLI, with no confirm) mid-sentence, and with
the split pane open it was not even the pane being typed in.

Close Session now has no default key: the capture-phase handler lets
Ctrl+W through and xterm sends ^W to whichever pane is focused. The
action stays in the registry and can be bound in App Settings ->
Shortcuts; the shortcut overlay shows it as not bound. The Help modal,
CLAUDE.md, the split and tile-grid specs and three wiki pages stop
advertising Ctrl+W as kill. Owner decision (tile-grid decision 5).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -276,7 +276,7 @@ Codeman is a Claude Code session manager with web interface and autonomous Ralph
 
 **Full-scrollback replay**: `GET /api/sessions/:id/terminal?full=1` returns the whole tmux scrollback ALONE (`source='mux-full-history'`), superseding the byte buffer. First load of each non-shell TUI session requests it (`_fullHistoryLoaded`); Shell selection and drop recovery use a bounded 1 MiB `?tail=`, and a Shell scroll-to-top pulls a bounded `?full=1&tail=` window (a window no longer than the browser's buffer is skipped before the downgrade guard, so it never marks the session exhausted); the unbounded pull stays behind **Load full history**. A Shell split-pane Pane B has its own copy of the bounded pull against its own xterm (`TerminalTile._pullHistory`, terminal-tile.js); keep the two in step. → [architecture-invariants#split-pane-sessions](docs/architecture-invariants.md#split-pane-sessions) ⚠️ The capture ends with a RELATIVE cursor move back to the pane's caret (never `CUP`), so no line-deleting transform may run over it; those skips key on `isFullCapture`, never on `?full=1` alone. ⚠️ A re-pull must never shrink the buffer (`_replayWouldShrinkBuffer()`). ⚠️ `captureCols`/`captureRows` are absent when no frame was positioned: test `Number.isFinite`, never truthiness. ⚠️ A frame dropped at the 128 KiB render cap MUST be recovered, and the recovery verifies itself: `_scheduleDroppedOutputRecovery` re-arms (bounded by `DROP_RECOVERY_MAX_ATTEMPTS`) while `_onSessionNeedsRefresh` reports no repaint, but never after a capture-fetch `'deadline'`. → [architecture-invariants#full-scrollback-replay](docs/architecture-invariants.md#full-scrollback-replay)
 
-**Split-pane sessions** (`showSplitButton`, header button, default OFF, desktop-only, per-device): a second live session ("Pane B") beside the active one, in a `TerminalTile` (terminal-tile.js; the picker, divider and auto-collapse stay in terminal-split.js) with its own xterm + WebSocket, resizable via a draggable divider. Pane B reconnects after a drop, sends input through the exactly-once queue over its own socket (`_registerInputSocket`), has clickable paths and image paste, and owns its geometry (no 40x10 floor, `zc` columns adopted, font changes call `tile.fit()`). ⚠️ Only typed input enters that persisted queue: xterm's query replies are dropped and focus/mouse reports go out ephemeral. ⚠️ App-level terminal actions find their pane through `_focusedPane()` (the terminal focused last), never `this.terminal`; Ctrl+W deliberately still closes `activeSessionId`. Still plainer than the primary pane (no local-echo overlay, CJK IME or touch handlers) and NOT persisted across reloads. The planned tile grid reuses `TerminalTile` (`docs/tile-grid-plan.md`). → [architecture-invariants#split-pane-sessions](docs/architecture-invariants.md#split-pane-sessions)
+**Split-pane sessions** (`showSplitButton`, header button, default OFF, desktop-only, per-device): a second live session ("Pane B") beside the active one, in a `TerminalTile` (terminal-tile.js; the picker, divider and auto-collapse stay in terminal-split.js) with its own xterm + WebSocket, resizable via a draggable divider. Pane B reconnects after a drop, sends input through the exactly-once queue over its own socket (`_registerInputSocket`), has clickable paths and image paste, and owns its geometry (no 40x10 floor, `zc` columns adopted, font changes call `tile.fit()`). ⚠️ Only typed input enters that persisted queue: xterm's query replies are dropped and focus/mouse reports go out ephemeral. ⚠️ App-level terminal actions find their pane through `_focusedPane()` (the terminal focused last), never `this.terminal`. Still plainer than the primary pane (no local-echo overlay, CJK IME or touch handlers) and NOT persisted across reloads. The planned tile grid reuses `TerminalTile` (`docs/tile-grid-plan.md`). → [architecture-invariants#split-pane-sessions](docs/architecture-invariants.md#split-pane-sessions)
 
 **Terminal touch gestures: link taps and text selection**: on touch devices xterm's linkifier and SelectionService never see the gesture, so both are driven explicitly (terminal-ui.js). ⚠️ A tap activates the link under it through the SAME provider as the hover linkifier (`_terminalLinkAtPoint`), synchronously inside `touchend` (keeps the user gesture `window.open` needs) and BEFORE any mouse report; the caret's logical line (`_tapIsOnCaretLine`) and TUI-owned rows (`_isActionableMobileTerminalTap`) keep their meaning. ⚠️ Gate on the caret line, never on tap intent (a shell calls every tap `'input'`). ⚠️ Long-press selects via xterm's public `select()`; keep the three guards: suppress the compat mouse pair after `touchend`, the bounded focus guard + `contextmenu` suppression for the platform long-press, and no closing `terminal.focus()` on phones. Tests: `test/terminal-touch-tap.test.ts`. → [architecture-invariants#terminal-touch-gestures-link-taps-and-text-selection](docs/architecture-invariants.md#terminal-touch-gestures-link-taps-and-text-selection)
 
@@ -389,7 +389,7 @@ Frontend JS modules have `@fileoverview` with `@dependency`/`@loadorder` tags. L
 
 **Respawn presets**: `solo-work` (3s/60min), `subagent-workflow` (45s/240min), `team-lead` (90s/480min), `ralph-todo` (8s/480min), `overnight-autonomous` (10s/480min).
 
-**Keyboard shortcuts**: Escape (close), Ctrl+? (shortcut overlay), Ctrl/Cmd/Alt+K (session palette), Ctrl+W (kill), Ctrl+Tab (next), Alt+[/] (prev/next tab), Alt+1-9 (switch tab), Ctrl+Shift+{/} (move tab left/right), Shift+Enter or Ctrl+Enter (newline), Ctrl+C (copy selection, else interrupt) / Ctrl+Shift+C (copy, never interrupts), Ctrl+L (clear), Ctrl+Shift+R (restore size), Ctrl+Shift+V (voice input), Ctrl/Cmd +/- (font), Shift+Wheel (local scrollback when mouse passthrough is active), Shift+drag (start a selection in a stripped-DECSET pane, where xterm's own Shift branch is unreachable and a Shift+drag used to select nothing; `_installShiftDragSelection`), right-click (copy the selection, the mintty/PuTTY convention, since xterm paints into a canvas and the native menu has no Copy for it; with nothing selected the native menu is left alone). Rebindable via the registry.
+**Keyboard shortcuts**: Escape (close), Ctrl+? (shortcut overlay), Ctrl/Cmd/Alt+K (session palette), Ctrl+Tab (next), Alt+[/] (prev/next tab), Alt+1-9 (switch tab), Ctrl+Shift+{/} (move tab left/right), Shift+Enter or Ctrl+Enter (newline), Ctrl+C (copy selection, else interrupt) / Ctrl+Shift+C (copy, never interrupts), Ctrl+L (clear), Ctrl+Shift+R (restore size), Ctrl+Shift+V (voice input), Ctrl/Cmd +/- (font), Shift+Wheel (local scrollback when mouse passthrough is active), Shift+drag (start a selection in a stripped-DECSET pane, where xterm's own Shift branch is unreachable and a Shift+drag used to select nothing; `_installShiftDragSelection`), right-click (copy the selection, the mintty/PuTTY convention, since xterm paints into a canvas and the native menu has no Copy for it; with nothing selected the native menu is left alone). Rebindable via the registry. ⚠️ **Ctrl+W is deliberately NOT bound** (owner decision): it is delete-word in every shell and agent CLI, and as Close Session it killed sessions with no confirm; `close-session` keeps `bindings: []` and stays bindable (`test/ctrl-w-never-closes.test.ts`).
 
 ### Security