feat: add SpecDialog component for editing spec frontmatter

- Implement SpecDialog for managing spec details including title, read mode, priority, and keywords.
- Add validation and keyword management functionality.
- Integrate SpecDialog into SpecsSettingsPage for editing specs.

feat: create index file for specs components

- Export SpecCard, SpecDialog, and related types from a new index file for better organization.

feat: implement SpecsSettingsPage for managing specs and hooks

- Create main settings page with tabs for Project Specs, Personal Specs, Hooks, Injection, and Settings.
- Integrate SpecDialog and HookDialog for editing specs and hooks.
- Add search functionality and mock data for specs and hooks.

feat: add spec management API routes

- Implement API endpoints for listing specs, getting spec details, updating frontmatter, rebuilding indices, and initializing the spec system.
- Handle errors and responses appropriately for each endpoint.

ccw/frontend/src/components/layout/Sidebar.tsx

@@ -26,6 +26,7 @@ import {
   Cog,
   Users,
   FileSearch,
+  ScrollText,
 } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { Button } from '@/components/ui/Button';
@@ -101,6 +102,7 @@ const navGroupDefinitions: NavGroupDef[] = [
     items: [
       { path: '/hooks', labelKey: 'navigation.main.hooks', icon: GitFork },
       { path: '/settings/mcp', labelKey: 'navigation.main.mcp', icon: Server },
+      { path: '/settings/specs', labelKey: 'navigation.main.specs', icon: ScrollText },
     ],
   },
   {