v1.21.0 — norafleet.ai domain migration

Highlights

• Nora has a new home: norafleet.ai. Every product-owned URL moves from nora.solomontsao.com to norafleet.ai, and the docs from noradocs.solomontsao.com to docs.norafleet.ai. Old URLs keep working through edge redirects (301, with method-preserving 308 for /api/* so existing API clients and self-hosted Agent Hub consumers are unaffected).
• Agent Hub default URL migrates itself. Append-only DB migrations update the platform_settings column default and rewrite rows still pointing at the old hosted hub; custom hub URLs are left untouched. No operator action required on upgrade.
• Kubernetes fleets keep their managed-env state. The tracking annotation is renamed to norafleet.ai/managed-env-names with a read-compatibility fallback for the legacy key; Deployments self-migrate on their next env update.
• Contact addresses move to privacy@ / legal@ / support@norafleet.ai.

Verification

• PR #431: all 63 CI checks green (quality, compose pipeline, security, CodeQL analyze, Playwright E2E).
• backend-api Jest: 2501 passed (includes a new legacy-annotation migration test); frontend-marketing: 16 passed; admin-dashboard helper + typecheck suites; infra-security / repository-metadata / extension-scaffold contract suites.
• Migration safety: the checksummed positional migrations in backend-api/server.ts are byte-identical to v1.20.0; new statements appended at the tail only.