chore: verify the admin site end to end

Everything checkable without a browser, against scratch databases:

- All five Go modules and the adminsite production build compile clean.
- Scoping holds: own instance 200, another account's 404, nonexistent 404 --
  indistinguishable, so no existence oracle -- and a customer session on the
  staff API gets 401 where staff gets 200.
- max_relinks comes from the API (3), not a constant mirrored in TypeScript.
- The inline blob and the download endpoint return byte-identical content, so
  the fallback is faithful rather than approximate.
- ADMIN_API_URL really is baked at build time: 9999 in the deliberately
  broken image, 8083 in the good one.
- The served stylesheet carries site/'s tokens with matching values, plus
  prefers-color-scheme and both data-theme overrides.
- With admin stopped the control plane still reports valid and mutations
  still succeed -- instances never call admin.
- Admin touched only the three licence fields on instances; every other
  control-plane collection is as the control plane left it.

Caught one stale-image bug doing this: the running admin predated the
customer blob change, so the licence response had no blob field at all.
Rebuilt and re-verified.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

adminsite/tsconfig.json

@@ -1,21 +1,41 @@
 {
-    "compilerOptions": {
-        "target": "ES2022",
-        "lib": ["dom", "dom.iterable", "esnext"],
-        "allowJs": false,
-        "skipLibCheck": true,
-        "strict": true,
-        "noEmit": true,
-        "esModuleInterop": true,
-        "module": "esnext",
-        "moduleResolution": "bundler",
-        "resolveJsonModule": true,
-        "isolatedModules": true,
-        "jsx": "preserve",
-        "incremental": true,
-        "plugins": [{ "name": "next" }],
-        "paths": { "@/*": ["./*"] }
-    },
-    "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
-    "exclude": ["node_modules"]
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": [
+      "dom",
+      "dom.iterable",
+      "esnext"
+    ],
+    "allowJs": false,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "react-jsx",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": [
+        "./*"
+      ]
+    }
+  },
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts",
+    ".next/dev/types/**/*.ts"
+  ],
+  "exclude": [
+    "node_modules"
+  ]
 }