Add bundle analyzer configuration

Configure @next/bundle-analyzer for production bundle analysis:

**Changes:**
- Install @next/bundle-analyzer package
- Update next.config.mjs to wrap config with bundle analyzer
- Add npm script `build:analyze` to run build with ANALYZE=true
- Bundle analyzer only enabled when ANALYZE=true environment variable is set

**Usage:**
```bash
# Run build with bundle analysis
npm run build:analyze

# Opens interactive bundle visualization in browser
# Shows chunk sizes, module dependencies, and optimization opportunities
```

**Note:** Kept Mastodon feed as Client Component (not Server Component)
because formatRelativeTime() uses `new Date()` which requires dynamic
rendering. Converting to Server Component would prevent static generation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

package.json

@@ -7,6 +7,7 @@
     "dev": "concurrently \"contentlayer2 dev\" \"next dev --turbo\"",
     "sync-assets": "node scripts/sync-assets.mjs",
     "build": "npm run sync-assets && contentlayer2 build && next build && npx pagefind --site .next && rm -rf public/_pagefind && cp -r .next/pagefind public/_pagefind",
+    "build:analyze": "ANALYZE=true npm run build",
     "start": "next start",
     "lint": "next lint",
     "contentlayer": "contentlayer build"
@@ -38,6 +39,7 @@
     "unist-util-visit": "^5.0.0"
   },
   "devDependencies": {
+    "@next/bundle-analyzer": "^16.0.3",
     "@tailwindcss/typography": "^0.5.19",
     "@types/node": "^24.10.1",
     "@types/react": "^19.2.5",