feat: add auto-generated titles for features

- Add POST /features/generate-title endpoint using Claude Haiku
- Generate concise titles (5-10 words) from feature descriptions
- Display titles in kanban cards with loading state
- Add optional title field to add/edit feature dialogs
- Auto-generate titles when description provided but title empty
- Add 'Pull & Resolve Conflicts' action to worktree dropdown
- Show running agents count in board header (X / Y format)
- Update Feature interface to include title and titleGenerating fields

apps/ui/src/lib/http-api-client.ts

@@ -512,6 +512,8 @@ export class HttpApiClient implements ElectronAPI {
       this.post("/api/features/delete", { projectPath, featureId }),
     getAgentOutput: (projectPath: string, featureId: string) =>
       this.post("/api/features/agent-output", { projectPath, featureId }),
+    generateTitle: (description: string) =>
+      this.post("/api/features/generate-title", { description }),
   };
 
   // Auto Mode API