feat: add task comments feature with CRUD operations

- Introduced a new `task_comments` table in the database schema.
- Implemented task comments API endpoints for listing, creating, and deleting comments.
- Enhanced the task detail dialog to display comments and allow users to add new comments.
- Updated task row component to handle click events for viewing task details.
- Added a theme provider to manage light/dark mode across the application.
- Refactored Milkdown editor to use Crepe for improved markdown editing experience.
- Updated global styles to accommodate new editor and theme changes.
- Enhanced task filtering and sorting functionality in the tasks page.

DEFAULT_PROMPT.md

@@ -23,21 +23,19 @@ APPEND to progress.txt (never replace, always append):
 
 ## USER REQUEST
 {
-  "id": "US-017",
-  "title": "Fluid Curtain pull-down animation",
-  "description": "As a user, I want to pull down from the top of any view to slide the app panel off-screen and reveal the AI chat layer beneath.",
+  "id": "US-018",
+  "title": "GitHub Copilot SDK setup and keytar token storage",
+  "description": "As a developer, I need the GitHub Copilot SDK initialized in the main process with secure OS keychain token storage so that AI features can authenticate.",
   "acceptanceCriteria": [
-    "framer-motion useMotionValue + useSpring (stiffness: 300, damping: 30) controls a 'y' CSS transform on the main app panel wrapper",
-    "Trigger 1: wheel event listener at document level — when the current route's scroll position is at 0 and deltaY < 0 (overscroll up), animate panel y from 0 to viewport height",
-    "Trigger 2: Cmd/Ctrl+K keyboard shortcut toggles curtain open (y = viewport height) and closed (y = 0)",
-    "AI chat view is rendered as a fixed full-screen layer behind the sliding panel and becomes fully visible when panel slides down",
-    "App panel remains mounted during animation (no unmount/remount, no state loss)",
-    "Returning from chat: wheel event with deltaY > 0 at chat-bottom OR Cmd/Ctrl+K slides panel back to y = 0",
-    "Right-edge vertical 'keep scrolling for AI' label with chevron-down is visible in every section (non-interactive, visual hint only)",
-    "Typecheck passes",
-    "Verify in browser using dev-browser skill"
+    "keytar installed and imported in main process only (not renderer)",
+    "ai.setToken tRPC mutation accepts { token: string } and stores it via keytar.setPassword('adiuva', 'copilot-token', token)",
+    "ai.hasToken tRPC query returns a boolean indicating whether a token is stored",
+    "On app start, main process reads the token from keychain and initializes the GitHub Copilot SDK client",
+    "Settings dialog uses shadcn/ui Dialog (DialogTrigger as a SidebarMenuButton with Settings/gear icon in the sidebar footer); dialog content uses shadcn/ui Input for token paste + shadcn/ui Button to save via ai.setToken",
+    "If no token is stored, AI-dependent features display a prompt using shadcn/ui Card with a shadcn/ui Button linking to the Settings dialog instead of throwing an error",
+    "Typecheck passes"
   ],
-  "priority": 17,
+  "priority": 18,
   "passes": false,
   "notes": ""
 }