refactor(desktop): make Tauri thin shell running web sidecar (#273)

## What / Why
This PR finishes the desktop refactor: the Tauri app is now a thin shell that launches the web server as a sidecar and loads the UI from `http://127.0.0.1:<port>`. All real backend logic lives in `packages/web/server/index.js`; desktop Rust keeps only native integrations (menu/dialog/notifications/updater/deep-link + window chrome).
This unblocks:
- consistent behavior across web/desktop/vscode (single backend)
- simpler desktop maintenance (no duplicated Rust backend)
- host switching between Local + remote instances in desktop
- reliable cold-start behavior on slow machines (VSCode + desktop)
## Key changes
- Desktop sidecar runtime
  - build pipeline to bundle web dist + `openchamber-server` sidecar (`packages/desktop/scripts/build-sidecar.mjs`)
  - robust local port selection (prefer saved/default, fallback to random; persisted in `~/.config/openchamber/settings.json`)
  - improved PATH handling so the sidecar can locate `opencode` CLI (incl `~/.opencode/bin`, overrides, common bins)
  - disable native right-click context menu in production builds (dev keeps it)
- Desktop instance switcher (Tauri-only)
  - header button + modal to add/edit/delete remote hosts, set default, probe status/ping, switch back to Local escape hatch
  - auth gate includes host switcher so you can recover when a remote host is broken/auth-required
  - host list stored desktop-locally (not tied to the currently selected remote server)
- Notifications
  - decision logic moved server-side; desktop notifications emitted via sidecar stdout and shown natively by Tauri
  - prevent double-notifications on desktop Local origin (UI ignores SSE notification when native path is active)
  - restore macOS notification sound
- Updates
  - Tauri updater used only when viewing Local instance in desktop shell (avoid “remote web update” triggering desktop restart)
- Settings persistence & UX polish
  - persist model favorites/recents via `/api/config/settings` (works for web + desktop; not origin-dependent)
  - persist per-project sidebar collapse state in `projects[].sidebarCollapsed` via `/api/config/settings` (with debounce on toggles)
  - macOS header sizing/traffic-lights offsets fixed (marketing macOS major injected from desktop; MultiRun header aligned)
  - VSCode cold-start: keep retrying provider/agent loads after connection to avoid empty UI on slow machines
  - misc lint/type fixes + bun.lock sync
- Desktop bootstrap / resiliency
  - show onboarding screen when OpenCode CLI is missing (desktop Local origin), with retry hook to restart OpenCode after install
## Testing notes
- Desktop (macOS): switch Local <-> remote, set default host, verify auth gate recovery, native notifications (with sound), updater gated to Local
- Web: favorites/recents + per-project collapsed state persist across reload/restart
- VSCode: slow startup no longer results in missing providers/agents/models

packages/ui/src/components/chat/StatusRow.tsx

@@ -53,8 +53,6 @@ interface StatusRowProps {
   isWaitingForPermission?: boolean;
   wasAborted?: boolean;
   abortActive?: boolean;
-  completionId?: string | null;
-  isComplete?: boolean;
   // Abort state (for mobile/vscode)
   showAbort?: boolean;
   onAbort?: () => void;
@@ -69,8 +67,6 @@ export const StatusRow: React.FC<StatusRowProps> = ({
   isWaitingForPermission,
   wasAborted,
   abortActive,
-  completionId,
-  isComplete,
   showAbort,
   onAbort,
   showAbortStatus,
@@ -124,17 +120,16 @@ export const StatusRow: React.FC<StatusRowProps> = ({
   const hasActiveTodos = visibleTodos.some((t) => t.status === "in_progress" || t.status === "pending");
   // Original logic from ChatInput
   const shouldRenderPlaceholder = !showAbortStatus && (wasAborted || !abortActive);
-  
-  // Track if placeholder is showing result (done/aborted) to keep StatusRow mounted
-  const [placeholderShowingResult, setPlaceholderShowingResult] = React.useState(false);
-  
+
   // Keep StatusRow rendered while:
   // - isWorking (active session)
-  // - isComplete (showing "Done" result)
-  // - wasAborted (showing "Aborted" result)
-  // - placeholderShowingResult (placeholder still displaying result)
-  // - hasActiveTodos or showAbortStatus
-  const hasContent = isWorking || isComplete || wasAborted || placeholderShowingResult || hasActiveTodos || showAbortStatus;
+  // - wasAborted / showAbortStatus
+  // - hasActiveTodos
+  const hasContent =
+    isWorking ||
+    Boolean(wasAborted) ||
+    Boolean(showAbortStatus) ||
+    hasActiveTodos;
 
   // Close popover when clicking outside
   const popoverRef = React.useRef<HTMLDivElement>(null);
@@ -212,13 +207,10 @@ export const StatusRow: React.FC<StatusRowProps> = ({
           ) : shouldRenderPlaceholder ? (
             <WorkingPlaceholder
               key={currentSessionId ?? "no-session"}
+              isWorking={isWorking}
               statusText={statusText}
               isGenericStatus={isGenericStatus}
               isWaitingForPermission={isWaitingForPermission}
-              wasAborted={wasAborted}
-              completionId={completionId ?? null}
-              isComplete={isComplete}
-              onResultVisibilityChange={setPlaceholderShowingResult}
             />
           ) : null}
         </div>