M1 (partial): tRPC API layer, storage, and three real fixes

Stands up packages/api so the swipe path stops trusting its caller, and
puts the auth library behind an interface we own.

- packages/api: tRPC v11 with a Session type WE define, not one
  re-exported from an auth library. Swapping providers means rewriting
  one SessionResolver, not touching a router.
- Procedure layers: public / protected / client / pro / verifiedPro /
  admin. Admin routes 404 rather than 403 so they cannot be probed.
- deck router replaces the untrusted server action. Ownership is checked
  on every operation and returns NOT_FOUND, never FORBIDDEN, so job ids
  cannot be enumerated. 23 tests, mostly authorization.
- packages/storage: presigned direct-to-R2 uploads. The server picks the
  key, so a caller can only write under their own user id. 14 tests.

Three defects found and fixed:
- The lazy db Proxy failed drizzle's is(db, PgDatabase) because it did
  not trap getPrototypeOf. Auth adapters dispatch on exactly that check,
  so this would have failed at runtime inside third-party code. Fixed
  and pinned with a regression test.
- The open-request cap was a read-then-write race: concurrent swipes
  could both read 4 and both insert. Now one transaction with the job
  row locked. The cap is checked before the tombstone is written, so a
  rejected swipe leaves no trace and the card stays on the deck.
- superjson was configured in two of the three required places. Without
  the QueryClient dehydrate/hydrate pair, RSC-prefetched data arrives as
  a raw envelope with no type error to warn you.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/web/next.config.ts

@@ -7,7 +7,7 @@ loadEnv({ path: '../../.env' });
 const config: NextConfig = {
   reactStrictMode: true,
   // The workspace packages ship TypeScript source, not build output.
-  transpilePackages: ['@linkder/db', '@linkder/shared'],
+  transpilePackages: ['@linkder/api', '@linkder/db', '@linkder/shared', '@linkder/storage'],
   images: {
     remotePatterns: [
       { protocol: 'https', hostname: 'picsum.photos' },