fix: harden and de-slop the merged sidebar/chat/settings batch

Post-merge follow-ups for #2740 #2735 #2734 #2690 #2676 #2738 #2684
#2689 #2733 #2739 #2462 #2687 #2736 #2618 #2697, plus three regressions
found while reviewing them:

- ctrl/cmd+digit while typing no longer switches session tabs (#2503 was
  still open in practice: the guard only covered the mod+alt surface binding)
- Shiki template-call sanitizer now covers every bundled grammar, including
  the js/ts aliases and embedding grammars; timed-out highlight requests are
  memoized and no longer cancel unrelated in-flight requests
- settings flush on suspend uses keepalive and also fires on Capacitor
  appStateChange; keeps the selected model persisted across mode switches
- remote-only branches fetch before checkout; range helpers fail clearly
- git status invalidation now fires for runtime adapters too
- settings number inputs and select triggers size in ch so they scale with
  the interface font
- recent-activity timestamps tick from one list-level ticker
- Markdown preview find goes through the shared find_in_file keybind with
  containment, no longer counts its own bar, and debounces observer runs
- #2676 reverted; #2524 fixed by fading the sticky header's own background
  instead of overlaying the content below it
- sticky group headers in the model picker and sidebar render again
  (oc-sticky-fade-scroller class restored after 9b9d7069c)
- project switcher names are left-aligned again (wrapper lost in 26dbc2f30)
- tool card quick-open icon is always visible and opens the same line as the
  expanded card's button
- tautological tests replaced or removed; new oxlint findings fixed

packages/ui/src/lib/shortcuts/DOCUMENTATION.md

@@ -31,6 +31,8 @@ The default layout follows three modes: single chords for everyday actions, the
 
 The internal `switch_tab_*` bindings remain available to mobile handlers. Desktop numeric context-surface switching is resolved by the configurable `switch_context_surface` prefix before normal dispatcher matching and falls through on mobile.
 
+Both digit prefixes yield when the event target is editable: an input, textarea, select, or contenteditable element. `switch_session_tab` defaults to a bare `mod` prefix, so without that guard plain ctrl/cmd+digit would switch tabs while the user is typing in the composer.
+
 The settings recorder captures up to two chords with at most three simultaneous physical keys per chord and checks the complete schema, not only customizable actions. After the first chord it waits up to 3000ms for a second; conflict and browser-risk feedback appears only when the second chord, timeout, or Confirm settles the recording. It keeps the recording local until the user clicks Confirm, allows an exact customizable conflict to replace the previous assignment, and blocks prefix conflicts unless the single-chord action explicitly allows sequence fallback. Those contextual prefixes remain saveable with a warning because their handler yields outside its owning context. Internal bindings are authoritative: persisted overrides cannot change or unassign them, and recorder conflicts with them cannot be replaced.
 
 `add_selection_to_chat` is contextual. A visible text-selection toolbar publishes its Add to chat and dismiss actions, suspends the shared application registry, and clears both synchronously when hidden or unmounted. The main application route also gates directly on active toolbar ownership before global dispatch, so unrelated shortcuts cannot escape the scoped interaction even if runtime bundling isolates registry state. The newest visible toolbar owns a dedicated scoped dispatcher; it ignores IME composition, stops IME Escape before the global Escape route without preventing its native default, handles non-IME Escape and the configured Add to chat binding (including a two-chord binding), and lets native input continue for unrelated keys. The application handler returns `false` when no toolbar action is active, so an unselected or stale DOM range can instead become a sequence leader. Opening, closing, or replacing a toolbar invalidates any pending scoped or global prefix.