Sign panel sessions and isolate test runs

- Replace in-memory auth sessions with signed cookies and signed OAuth state
- Add auth route coverage and update panel/web server wiring
- Switch test script to per-file Bun processes and clean up type checks

tsconfig.json

@@ -2,7 +2,9 @@
   "compilerOptions": {
     // Environment setup & latest features
     "lib": [
-      "ESNext"
+      "ESNext",
+      "DOM",
+      "DOM.Iterable"
     ],
     "target": "ESNext",
     "module": "Preserve",
@@ -54,4 +56,4 @@
     "dist",
     "drizzle"
   ]
-}
+}