feat(p11): temps réel complet (watcher checkout principal + topic settings)

P11-A — branche du checkout principal modifiée hors Arboretum :
- fs-watcher: pin « permanent » non évinçable (pinRepo/unpinRepo, repoPins dans evictIfNeeded)
- worktree-manager: armMainCheckoutWatchers() + arm/désarm sur addRepo/découverte/removeRepo/hidden
- index.ts: armMainCheckoutWatchers() dans runDaemon → git checkout CLI sur le principal → worktree_update <500ms sans watch client

P11-B — réglages en temps réel :
- protocole additif: type SettingsBroadcast (source unique, réutilisé par SettingsResponse), topic 'settings', message settings_update (validés parseClientMessage + gateway)
- core/settings-bus.ts (EventEmitter) ; routes/settings émet après PATCH ; gateway relaie aux abonnés 'settings'
- web: ws-client subscribeSettings + routage ; store settings applySettings/startRealtime ; AppShell abonne globalement ; SettingsView re-sync des drafts scalaires sans écraser une saisie en cours
- tests: protocol (topic settings) + fs-watcher (pinRepo non évincé) ; acceptance-p11.mjs (checkout principal <500ms + settings_update)

packages/web/src/lib/ws-client.ts

@@ -29,6 +29,8 @@ export interface TerminalSink {
 export type SessionEvent = Extract<ServerMessage, { type: 'session_update' | 'session_exit' | 'session_archived' }>;
 export type WorktreeEvent = Extract<ServerMessage, { type: 'repo_update' | 'repo_removed' | 'worktree_update' | 'worktree_removed' }>;
 export type GroupEvent = Extract<ServerMessage, { type: 'group_update' | 'group_removed' }>;
+/** P11 — un réglage a changé (diffusé au topic 'settings'). */
+export type SettingsUpdateEvent = Extract<ServerMessage, { type: 'settings_update' }>;
 /** P7 — signal ciblé « le détail (changes/diff) d'un worktree regardé a changé ». */
 export type WorktreeChangesEvent = Extract<ServerMessage, { type: 'worktree_changes' }>;
 
@@ -127,6 +129,7 @@ export class WsClient {
   private readonly sessionListeners = new Set<(e: SessionEvent) => void>();
   private readonly worktreeListeners = new Set<(e: WorktreeEvent) => void>();
   private readonly groupListeners = new Set<(e: GroupEvent) => void>();
+  private readonly settingsListeners = new Set<(e: SettingsUpdateEvent) => void>();
   /** P7 — abonnements ciblés au détail d'un worktree (clé repoId\0path → listeners). */
   private readonly worktreeChangesListeners = new Map<string, Set<(e: WorktreeChangesEvent) => void>>();
 
@@ -177,11 +180,12 @@ export class WsClient {
   }
 
   /** topics actifs = union des abonnements courants (une seule connexion partagée). */
-  private activeTopics(): Array<'sessions' | 'worktrees' | 'groups'> {
-    const t: Array<'sessions' | 'worktrees' | 'groups'> = [];
+  private activeTopics(): Array<'sessions' | 'worktrees' | 'groups' | 'settings'> {
+    const t: Array<'sessions' | 'worktrees' | 'groups' | 'settings'> = [];
     if (this.sessionListeners.size > 0) t.push('sessions');
     if (this.worktreeListeners.size > 0) t.push('worktrees');
     if (this.groupListeners.size > 0) t.push('groups');
+    if (this.settingsListeners.size > 0) t.push('settings');
     return t;
   }
 
@@ -219,6 +223,16 @@ export class WsClient {
     };
   }
 
+  subscribeSettings(listener: (e: SettingsUpdateEvent) => void): () => void {
+    this.settingsListeners.add(listener);
+    this.connect();
+    this.sendSub();
+    return () => {
+      this.settingsListeners.delete(listener);
+      this.sendSub();
+    };
+  }
+
   /**
    * P7 — observe le détail (changes/diff) d'un worktree précis : envoie `watch`, route les
    * `worktree_changes` correspondants vers `listener`, et ré-arme automatiquement après reconnexion.
@@ -487,6 +501,10 @@ export class WsClient {
         for (const cb of this.groupListeners) cb(msg);
         return;
       }
+      case 'settings_update': {
+        for (const cb of this.settingsListeners) cb(msg);
+        return;
+      }
       case 'worktree_changes': {
         const set = this.worktreeChangesListeners.get(`${msg.repoId}\0${msg.path}`);
         if (set) for (const cb of set) cb(msg);