feat: externalize buttplug as separate nginx container

- Add Dockerfile.buttplug: builds Rust/WASM + TS, serves via nginx
- Add nginx.buttplug.conf: serves /dist and /wasm with correct MIME types
- Add .gitea/workflows/docker-build-buttplug.yml: path-filtered CI workflow
- Strip Rust toolchain and buttplug build from frontend Dockerfile
- Move buttplug to devDependencies (types only at build time)
- Remove vite-plugin-wasm from frontend (WASM now served by nginx)
- Add /buttplug proxy in vite.config (dev: localhost:8080)
- Add buttplug service to compose.yml
- Load buttplug dynamically in play page via runtime import
- Fix faq page: suppress no-unnecessary-state-wrap for reassigned SvelteSet

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/frontend/package.json

@@ -12,6 +12,7 @@
     "check": "svelte-check --tsconfig ./tsconfig.json --threshold warning"
   },
   "devDependencies": {
+    "@sexy.pivoine.art/buttplug": "workspace:*",
     "@iconify-json/ri": "^1.2.10",
     "@iconify/tailwind4": "^1.2.1",
     "@internationalized/date": "^3.11.0",
@@ -42,7 +43,6 @@
     "vite-plugin-wasm": "3.5.0"
   },
   "dependencies": {
-    "@sexy.pivoine.art/buttplug": "workspace:*",
     "@sexy.pivoine.art/types": "workspace:*",
     "graphql": "^16.11.0",
     "graphql-request": "^7.1.2",