feat: add /playground page for AI image generation

New page at /playground that lets visitors generate images using the
existing Venice AI and FAL AI backend APIs. Includes model selector
(z-image-turbo, chroma, SD 3.5, HiDream, Qwen Image), aspect ratio
picker, loading state, error handling, and hover-to-reveal "open"
overlay on the result. Fully theme-aware across all three themes.

Also registers the route in the menu, keyboard nav ([ / ]), and CLAUDE.md.

https://claude.ai/code/session_01WS3k66JckjG5u9Qypm2gdN

Author: claude

CLAUDE.md

@@ -29,6 +29,7 @@ pages/               — file-based routing
   guestbook.vue      — /guestbook — visitor guestbook (D1-backed, rate-limited per IP per 24h)
   activity.vue       — /activity — unified timeline: commits + Bluesky posts + guestbook entries
   stats.vue          — /stats — coding stats: language breakdown, top repos, commit heatmap
+  playground.vue     — /playground — AI image generation interface (uses /api/generate-image)
   drafts/            — experimental pages
 components/          — Vue components
 composables/         — useTheme
@@ -71,6 +72,6 @@ Three themes: **Scandinavian Glass** (default), **Cyberpunk**, **Space**.
 ## Keyboard Shortcuts
 
 - `M` key toggles the global menu (disabled on admin pages)
-- `[` / `]` navigate to previous / next page in order: `/`, `/about`, `/projects`, `/feed`, `/now`, `/uses`, `/guestbook`, `/activity`, `/stats`, `/meta`
+- `[` / `]` navigate to previous / next page in order: `/`, `/about`, `/projects`, `/feed`, `/now`, `/uses`, `/guestbook`, `/activity`, `/stats`, `/meta`, `/playground`
 - `1` / `2` / `3` switch themes (scandinavian / hacker / space)
 - `?` or `/` toggles the keyboard shortcuts overlay

app.vue

@@ -27,7 +27,7 @@ const showPalette = ref(false);
 const router = useRouter();
 const route = useRoute();
 
-const NAV_PAGES = ['/', '/about', '/projects', '/feed', '/now', '/uses', '/guestbook', '/activity', '/stats', '/meta'];
+const NAV_PAGES = ['/', '/about', '/projects', '/feed', '/now', '/uses', '/guestbook', '/activity', '/stats', '/meta', '/playground'];
 
 useHead({
   meta: [