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>

src/web/public/app.js

@@ -419,7 +419,14 @@ const DEFAULT_SHORTCUTS = [
     id: 'close-session',
     group: 'Session',
     label: 'Close Session',
-    bindings: [{ modifiers: ['ctrl'], key: 'w' }],
+    // ⚠️ No default key. This used to be Ctrl+W, which is "delete the previous
+    // word" in every shell, readline prompt and agent CLI, so muscle memory
+    // killed the session (tmux and the CLI, with no confirm) mid-sentence, and
+    // with the split open it was not even the pane being typed in. Ctrl+W now
+    // reaches the terminal like any other key. Closing stays on the tab's close
+    // control and menu (with their confirm), and anyone who wants a key binds
+    // one in App Settings → Shortcuts.
+    bindings: [],
     action: 'killActiveSession',
   },
   {
@@ -9134,6 +9141,9 @@ class CodemanApp {
     const fmtBindings = (s) => {
       if (s.displayBindings) return s.displayBindings.map((b) => `<kbd>${escapeHtml(b)}</kbd>`).join(' / ');
       if (!s.bindings) return '';
+      // An action with no key (Close Session by default) is still listed, so the
+      // overlay says so instead of showing an empty key column.
+      if (s.bindings.length === 0) return '<span class="shortcut-overlay-unbound">not bound</span>';
       return s.bindings.map((b) => {
         const parts = [...(b.modifiers || []).map((m) => m.charAt(0).toUpperCase() + m.slice(1)), b.key || b.code || ''];
         return `<kbd>${escapeHtml(parts.join('+'))}</kbd>`;

src/web/public/index.html

@@ -807,7 +807,6 @@
           <section class="shortcut-section">
             <h4>Session</h4>
             <div class="shortcuts-grid">
-              <div><kbd>Ctrl</kbd>+<kbd>W</kbd></div><div>Close Session</div>
               <div><kbd>Ctrl/Cmd/Option</kbd>+<kbd>K</kbd></div><div>Find Open Session</div>
               <div><kbd>Ctrl</kbd>+<kbd>Tab</kbd></div><div>Next Session</div>
               <div><kbd>Alt/Option</kbd>+<kbd>[</kbd> / <kbd>Alt/Option</kbd>+<kbd>]</kbd></div><div>Previous / Next Session</div>

src/web/public/styles.css

@@ -8520,6 +8520,12 @@ kbd {
   color: var(--text-dim);
 }
 
+/* An action with no key bound (Close Session by default): say so, quietly. */
+.shortcut-overlay-unbound {
+  font-size: 0.75rem;
+  font-style: italic;
+}
+
 .shortcut-overlay-footer {
   margin-top: 0.75rem;
   padding-top: 0.75rem;