feat(mobile): mobile app navigation rework and beta-feedback closeout (#2561)

Navigation model rebuilt around two full-width drawers and a minimal
header (sessions / title-switcher / usage ring / workspace):

- Left sessions drawer: cross-project tree with live status indicators,
  swipe actions on sessions (rename/archive/delete) and on group headers
  (project edit / two-step close, worktree delete), reorder-only edit
  mode with collapsible project cards and draggable worktrees, app-level
  footer (connected instance, settings, pending web update).
- Right workspace drawer: Changes / Files / Terminal / Notes / MCP as
  pill tabs (inactive tabs icon-only); panes stay mounted once visited.
  The full desktop file editor serves the Files tab; read/skill tool taps
  in chat open the file there at the requested line.
- Header session switcher on title tap: 10 cross-project recents with
  live busy/attention indicators and project · branch metadata; the
  usage ring opens a metadata overlay with an explicit loading state.
- The overflow menu is gone on phones (its destinations moved into the
  drawers); iPad keeps it until its dedicated layout pass.

Correctness and continuity:

- /auth/session answers bearer-first, so a stale WebView cookie can no
  longer mask a revoked device token; cold launches classify failures
  fast and land on an explicit connect screen.
- Authoritative session snapshots raise frozen ordering baselines and
  stale live ranks — recents stay truthful after the app slept.
- Cold launches reopen the last active session per instance (persisted
  pointer, confirmed against a sessions snapshot; a user-opened draft
  clears it), with a logo hold instead of a draft flash.

Also: collapsed pill composer gains the stop control; chat tool rows
share one 36px rhythm; Task subtool rows truncate; larger bottom safe
area so the composer clears big-screen corner radii; Capacitor build
hides About/Update (store updates apply there); widgets link to the
sessions drawer with a list icon; MobileApp split into focused modules;
five mobile-surface detectors unified; translucent borders normalized to
70%; all new strings translated across the 10 locales.

iPad and foldable layouts are intentionally untouched - separate next version PR.

packages/ui/src/apps/MobileChangesSurface.tsx

@@ -42,7 +42,7 @@ const isUnstagedStatusFile = (file: GitStatus['files'][number]): boolean => {
 const diffCacheKey = (path: string, staged: boolean): string => staged ? `${path}\u0000staged` : path;
 
 type MobileChangesSurfaceProps = {
-  /** When provided, the list header gets a close X that calls this; used when the surface is hosted in MobileSurfaceShell. */
+  /** When provided, the list header gets a close X that calls this. */
   onClose?: () => void;
   /**
    * When set (and non-null), the surface opens directly into the per-file diff view for this
@@ -541,7 +541,7 @@ export const MobileChangesSurface: React.FC<MobileChangesSurfaceProps> = ({ onCl
               onVisiblePathsChange={setVisibleChangePaths}
             />
           </div>
-          <div className="shrink-0 border-t border-border/50 px-4 pb-4 pt-3">
+          <div className="shrink-0 border-t border-border/70 px-4 pb-4 pt-3">
             <CommitSection
               stagedCount={stagedChangeEntries.length}
               commitMessage={commitMessage}
@@ -596,7 +596,7 @@ const MobileDiffDetail: React.FC<{
 
   return (
     <div className="flex h-full flex-col overflow-hidden bg-background text-foreground">
-      <header className="flex h-[var(--oc-header-height,56px)] shrink-0 items-center gap-3 border-b border-border/50 px-3 text-foreground">
+      <header className="flex h-[var(--oc-header-height,56px)] shrink-0 items-center gap-3 border-b border-border/70 px-3 text-foreground">
         <button
           type="button"
           className="flex size-9 shrink-0 items-center justify-center rounded-lg text-muted-foreground hover:bg-interactive-hover hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary"