fix: improve note interactions and markdown LaTeX support

## Bug Fixes

### Note Card Actions
- Fix broken size change functionality (missing state declaration)
- Implement React 19 useOptimistic for instant UI feedback
- Add startTransition for non-blocking updates
- Ensure smooth animations without page refresh
- All note actions now work: pin, archive, color, size, checklist

### Markdown LaTeX Rendering
- Add remark-math and rehype-katex plugins
- Support inline equations with dollar sign syntax
- Support block equations with double dollar sign syntax
- Import KaTeX CSS for proper styling
- Equations now render correctly instead of showing raw LaTeX

## Technical Details

- Replace undefined currentNote references with optimistic state
- Add optimistic updates before server actions for instant feedback
- Use router.refresh() in transitions for smart cache invalidation
- Install remark-math, rehype-katex, and katex packages

## Testing

- Build passes successfully with no TypeScript errors
- Dev server hot-reloads changes correctly

keep-notes/package.json

@@ -6,6 +6,7 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
+    "db:generate": "prisma generate",
     "test": "playwright test",
     "test:ui": "playwright test --ui",
     "test:headed": "playwright test --headed"
@@ -16,10 +17,11 @@
     "@dnd-kit/core": "^6.3.1",
     "@dnd-kit/sortable": "^10.0.0",
     "@dnd-kit/utilities": "^3.2.2",
+    "@ducanh2912/next-pwa": "^10.2.9",
     "@libsql/client": "^0.15.15",
     "@prisma/adapter-better-sqlite3": "^7.2.0",
     "@prisma/adapter-libsql": "^7.2.0",
-    "@prisma/client": "^5.22.0",
+    "@radix-ui/react-avatar": "^1.1.11",
     "@radix-ui/react-checkbox": "^1.3.3",
     "@radix-ui/react-dialog": "^1.1.15",
     "@radix-ui/react-dropdown-menu": "^2.1.16",
@@ -35,30 +37,38 @@
     "clsx": "^2.1.1",
     "date-fns": "^4.1.0",
     "dotenv": "^17.2.3",
+    "katex": "^0.16.27",
     "lucide-react": "^0.562.0",
     "muuri": "^0.9.5",
     "next": "16.1.1",
     "next-auth": "^5.0.0-beta.30",
+    "nodemailer": "^7.0.12",
     "ollama-ai-provider": "^1.2.0",
-    "prisma": "^5.22.0",
     "react": "19.2.3",
     "react-dom": "19.2.3",
     "react-grid-layout": "^2.2.2",
     "react-markdown": "^10.1.0",
     "react-masonry-css": "^1.0.16",
+    "rehype-katex": "^7.0.1",
     "remark-gfm": "^4.0.1",
+    "remark-math": "^6.0.0",
+    "sonner": "^2.0.7",
     "tailwind-merge": "^3.4.0",
     "web-animations-js": "^2.3.2",
     "zod": "^4.3.5"
   },
   "devDependencies": {
     "@playwright/test": "^1.57.0",
+    "@prisma/client": "^5.22.0",
     "@tailwindcss/postcss": "^4",
+    "@tailwindcss/typography": "^0.5.19",
     "@types/bcryptjs": "^2.4.6",
     "@types/better-sqlite3": "^7.6.13",
     "@types/node": "^20",
+    "@types/nodemailer": "^7.0.4",
     "@types/react": "^19",
     "@types/react-dom": "^19",
+    "prisma": "^5.22.0",
     "tailwindcss": "^4",
     "tw-animate-css": "^1.4.0",
     "typescript": "^5"