icons from extensions, settings-based tab ordering, static context tabs

Icons now declared on TabContribution via the icon field — the
hardcoded switch in _BottomRail is a fallback only. All sidebar
and context extensions set their Phosphor icon explicitly.

PanelRegistry supports setTabOrder(slot, List<String>) — tabs
render in the order specified by project.layout.sidebar.order /
context.order in settings.yaml. Falls back to registration order.
Priority field removed from all contributions.

Context tabs are static again — persist with their last content,
selection just loads new data and switches focus. No spawn/despawn.

Tickets sidebar priority set to -200 (leftmost, default open).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/builtin/pql/src/extension.dart

@@ -1,9 +1,8 @@
-import 'dart:async';
-
 import 'package:clide/builtin/pql/src/backlinks_view.dart';
 import 'package:clide/builtin/pql/src/pql_panel_view.dart';
 import 'package:clide/extension/extension.dart';
 import 'package:clide/kernel/kernel.dart';
+import 'package:clide/widgets/widgets.dart';
 
 class PqlExtension extends ClideExtension {
   @override
@@ -11,14 +10,10 @@ class PqlExtension extends ClideExtension {
   @override
   String get title => 'pql';
   @override
-  String get version => '0.2.0';
+  String get version => '0.3.0';
   @override
   List<String> get dependsOn => const [];
 
-  ClideExtensionContext? _ctx;
-  StreamSubscription<DaemonEvent>? _editorSub;
-  bool _backlinksSpawned = false;
-
   @override
   List<ContributionPoint> get contributions => [
         TabContribution(
@@ -27,46 +22,17 @@ class PqlExtension extends ClideExtension {
           title: 'pql',
           titleKey: 'tab.title',
           i18nNamespace: id,
+          icon: PhosphorIcons.magnifyingGlass,
           priority: -60,
           build: (_) => const PqlPanelView(),
         ),
+        TabContribution(
+          id: 'pql.backlinks',
+          slot: Slots.contextPanel,
+          title: 'Links',
+          icon: PhosphorIcons.link,
+          priority: -80,
+          build: (_) => const BacklinksView(),
+        ),
       ];
-
-  @override
-  Future<void> activate(ClideExtensionContext ctx) async {
-    _ctx = ctx;
-    _editorSub = ctx.events.on<DaemonEvent>().listen((e) {
-      if (e.subsystem != 'editor') return;
-      if (e.kind == 'editor.active-changed' || e.kind == 'editor.opened') {
-        _spawnBacklinks();
-      }
-    });
-  }
-
-  @override
-  Future<void> deactivate() async {
-    _editorSub?.cancel();
-    _despawnBacklinks();
-  }
-
-  void _spawnBacklinks() {
-    final ctx = _ctx;
-    if (ctx == null || _backlinksSpawned) return;
-    ctx.panels.contribute(TabContribution(
-      id: 'pql.backlinks',
-      slot: Slots.contextPanel,
-      title: 'Links',
-      priority: -80,
-      build: (_) => const BacklinksView(),
-    ));
-    _backlinksSpawned = true;
-    ctx.panels.activateTab(Slots.contextPanel, 'pql.backlinks');
-  }
-
-  void _despawnBacklinks() {
-    if (_backlinksSpawned) {
-      _ctx?.panels.uncontribute('pql.backlinks');
-      _backlinksSpawned = false;
-    }
-  }
 }