rework session layer on PasswordSession + three-client pattern

- PasswordSession (@atproto/lex-password-session) is now the single auth
  core; SessionAgent bridges it to the base Agent from @atproto/api so
  the ~148 useAgent() consumer files keep working unchanged
- SessionBundle carries {session, agent, accountClient, appviewClient};
  useLexClient() now returns the authed appview client, new
  useAppviewClient()/usePdsClient() hooks
- reducer: OpaqueSessionBundle, new replaced-current-bundle action for
  network-free cross-tab same-did sync (PasswordSession is immutable, so
  the bundle is rebuilt instead of mutated in place)
- moderation: AtpAgent.configure -> Client.configure + Agent.configure,
  per-account labelers on both the bridge and the appview client
- push-token unregistration uses temporary PasswordSessions
- hard-tail migrations: SignupQueued refresh via resumeSession shim,
  useBeginAgeAssurance scoped-token raw Client, useAccountEmailState
  reads currentAccount
- PDS routing preserved on the no-network resume fast path by
  synthesizing a minimal didDoc from the persisted pdsUrl

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

oxlint-suppressions.json

@@ -1483,11 +1483,6 @@
       "count": 1
     }
   },
-  "src/state/session/agent.ts": {
-    "typescript/no-explicit-any": {
-      "count": 1
-    }
-  },
   "src/state/shell/color-mode.tsx": {
     "typescript/no-floating-promises": {
       "count": 2