Merge origin/main into chore/remove-local-mode

Resolves conflicts after main merged parallel cleanup PRs (#1528, #1533,
#1534, #1536, #1537, #1538) that removed both openclaw-plugins packages.
Takes main's direction on:
- openclaw-plugins/manifest-model-router removal (main deleted both)
- docker-compose.yml local-testing framing (main's choice)
- Dockerfile healthcheck start-period=45s (main's fix)

Keeps this branch's unique contributions:
- Backend: delete all local-mode source files (LocalAuthGuard,
  local-mode.constants, local-bootstrap.service, limit-check-local,
  version-check.service), simplify sql-dialect.ts to Postgres-only,
  drop sql.js dep, remove backend-sqljs CI job
- Frontend: delete services/local-mode.ts, VersionIndicator component,
  remove isLocalMode/isDevMode branches across ~14 components
- AUTO_MIGRATE env var in database.module.ts + seeder
- Unified EMAIL_* env var scheme in send-email.ts + app.config.ts +
  notification-email.service.ts (covers both Better Auth transactional
  and threshold alerts via existing fallback)
- Docker compose: add AUTO_MIGRATE, EMAIL_*, OAuth env var passthroughs;
  drop MANIFEST_TRUST_LAN (dead after LocalAuthGuard removal)
- backend/.env.example: new EMAIL_* block, deprecate legacy MAILGUN_*
- Rewrite E2E test helpers to use Postgres (was sql.js)

Author: brunobuddy

.changeset/agent-type-select.md

@@ -0,0 +1,4 @@
+---
+---
+
+Docs: restructure supported providers table in README to show API key and subscription support per provider.