feat: add icon picker for tags with Iconify integration

- Add icon field to tag creation/update API and handlers
- Install @iconify packages (json, types, utils) as production deps
- Build IconPicker component for tag admin UI
- Fix apiFetch lazy initialization for build-time safety
- Update Docker to install production dependencies for SSR runtime

web/package.json

@@ -20,6 +20,9 @@
     "@fontsource-variable/schibsted-grotesk": "^5.2.8",
     "@fontsource/hanken-grotesk": "^5.1.0",
     "@fontsource/schibsted-grotesk": "^5.2.8",
+    "@iconify/json": "^2.2.425",
+    "@iconify/types": "^2.0.0",
+    "@iconify/utils": "^3.1.0",
     "@logtape/logtape": "^1.3.5",
     "@resvg/resvg-js": "^2.6.2",
     "@xevion/satori-html": "^0.4.1",
@@ -32,7 +35,6 @@
   "devDependencies": {
     "@eslint/js": "^9.39.2",
     "@fontsource/inter": "^5.2.8",
-    "@iconify/json": "^2.2.424",
     "@sveltejs/kit": "^2.21.0",
     "@sveltejs/vite-plugin-svelte": "^6.2.1",
     "@tailwindcss/vite": "^4.1.11",