merge: integrate main into dev

Resolve 9 merge conflicts preserving both sides' intent:
- nix hash, bootstrap hostnames rename, websocket-server wiring
- session.ts handler dedup, snapshot fallback, worktree registration
- worktree-session git service + script/setup features
- sidebar-workspace-list setup navigation, session-context cleanup
- workspace-registry-bootstrap test kept (code still exists)
- checkout-git test additions from both sides

Post-merge fixes: isPaneFocused prop rename, server type rebuild.

packages/app/src/keyboard/keyboard-shortcuts.ts

@@ -788,6 +788,32 @@ const SHORTCUT_BINDINGS: readonly ShortcutBinding[] = [
   },
 
   // --- Message input ---
+  {
+    id: "message-input-focus-cmd-l-mac",
+    action: "message-input.action",
+    combo: "Cmd+L",
+    when: { mac: true, commandCenter: false },
+    payload: { type: "message-input", kind: "focus" },
+    help: {
+      id: "focus-message-input",
+      section: "agent-input",
+      label: "Focus message input",
+      keys: ["mod", "L"],
+    },
+  },
+  {
+    id: "message-input-focus-ctrl-l-non-mac",
+    action: "message-input.action",
+    combo: "Ctrl+L",
+    when: { mac: false, commandCenter: false, terminal: false },
+    payload: { type: "message-input", kind: "focus" },
+    help: {
+      id: "focus-message-input",
+      section: "agent-input",
+      label: "Focus message input",
+      keys: ["mod", "L"],
+    },
+  },
   {
     id: "message-input-voice-toggle-cmd-shift-d-mac",
     action: "message-input.action",