make sidebar filter boxes CLI-addressable via the MessageBus (T-270)

The sidebar/dock filter fields (the shared ClideFilterBox) had no CLI
peer — a one-way, UI-only affordance that broke D-6 parity. Add the
drive+observe verb `clide ui filter <address> [<text>]`, routed entirely
through the kernel MessageBus pub/sub so a box reacts to a published
message identically whether the trigger was a UI keystroke or the CLI —
keeping extensions first-class (no dispatcher→widget wiring).

- ClideFilterBox gains an `address`; when set it listens on `filter.set`
  for its address and republishes its value on `filter.state`. Null
  address keeps the box a kernel-free UI widget.
- FilterStateCache (new kernel service) caches the latest `filter.state`
  per address — the bus has no retention, so this backs the observe-half.
- ui.filter: with text → publishes `filter.set` (drive); without →
  reads the cache (observe). Honest toolError when there is no live UI.
- Address every box: decisions/tickets/files/git/output/problems panes,
  the four search boxes, and the pql search/query/markdown inputs.

Addresses are the ids from `clide pane list` (e.g. decisions.panel).
settings.json: allow the `clide` CLI + relevant skills.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/builtin/search/src/search_panel_view.dart

@@ -105,7 +105,7 @@ class _SearchPanelViewState extends State<SearchPanelView> {
               child: Column(
                 crossAxisAlignment: CrossAxisAlignment.stretch,
                 children: [
-                  ClideFilterBox(hint: 'Search', onChanged: c.run, onSubmitted: c.run),
+                  ClideFilterBox(address: 'search.findInFiles', hint: 'Search', onChanged: c.run, onSubmitted: c.run),
                   const SizedBox(height: 6),
                   Row(
                     children: [
@@ -137,7 +137,9 @@ class _SearchPanelViewState extends State<SearchPanelView> {
                   const SizedBox(height: 6),
                   Row(
                     children: [
-                      Expanded(child: ClideFilterBox(hint: 'Replace', icon: null, debounce: Duration.zero, onChanged: c.setReplacement)),
+                      Expanded(
+                          child: ClideFilterBox(
+                              address: 'search.findInFiles.replace', hint: 'Replace', icon: null, debounce: Duration.zero, onChanged: c.setReplacement)),
                       const SizedBox(width: 6),
                       _ReplaceAllButton(
                         enabled: c.replacement.isNotEmpty && c.matchCount > 0,
@@ -147,9 +149,15 @@ class _SearchPanelViewState extends State<SearchPanelView> {
                     ],
                   ),
                   const SizedBox(height: 6),
-                  ClideFilterBox(hint: 'files to include (e.g. *.dart)', icon: null, debounce: Duration.zero, onChanged: (v) => c.include = v),
+                  ClideFilterBox(
+                      address: 'search.findInFiles.include',
+                      hint: 'files to include (e.g. *.dart)',
+                      icon: null,
+                      debounce: Duration.zero,
+                      onChanged: (v) => c.include = v),
                   const SizedBox(height: 4),
-                  ClideFilterBox(hint: 'files to exclude', icon: null, debounce: Duration.zero, onChanged: (v) => c.exclude = v),
+                  ClideFilterBox(
+                      address: 'search.findInFiles.exclude', hint: 'files to exclude', icon: null, debounce: Duration.zero, onChanged: (v) => c.exclude = v),
                 ],
               ),
             ),