feat(agent-email): add GET /v1/email/init readiness preflight (#1795)

docs/guides/email.mdx

@@ -329,7 +329,8 @@ isolated, and dogfoods the exact binary shipped to integrators.
 `GAIA_EMAIL_AGENT_MODE` only selects which *process* answers (`user` default /
 `dev`); there is no in-process fallback. Two surfaces run through it:
 
-- **The `/v1/email/*` REST surface** — the full schema-2.2 contract (triage,
+- **The `/v1/email/*` REST surface** — the full schema-2.2 contract (init
+  readiness probe + provisioning, triage,
   batch triage, search, inbox pre-scan, scheduled daily briefing, draft/send +
   confirm — attachments included, archive/unarchive, quarantine/unquarantine,
   calendar view/preview/create/respond, health, version). This is exactly what

hub/agents/python/email/gaia-agent.yaml

@@ -27,6 +27,11 @@ python:
 
 requirements:
   min_memory_gb: 8
+  # Minimum Lemonade Server version the triage stack needs. Mirrors
+  # gaia_agent_email.version.MIN_LEMONADE_VERSION (the runtime source of truth
+  # for the GET /v1/email/init readiness check); a test keeps the two in
+  # lock-step. `gaia init` reads this manifest value for the install path.
+  min_lemonade_version: "10.2.0"
   platforms: [win-x64, linux-x64, darwin-arm64]
 
 interfaces: