EPIC: Connector platform and domain packs

Programme: #1

Own connector contracts, account/auth isolation, protocol adapters, compatibility extraction and production-access health. Services are treated as typed data/action providers, not as the user's mandatory presentation layer.

## Child issues
- [ ] #45 CONN-01 — Connector SDK, registry and manifests
- [ ] #46 CONN-02 — Identity/auth lifecycle and account isolation
- [ ] #47 CONN-03 — Protocol adapters and compatibility extraction
- [ ] #48 CONN-04 — Connector health, permissions and partner access

## Cross-cutting gates
Exact read/write schemas, account isolation, truthful support levels, API/MCP/WebMCP/browser-fallback separation, schema drift/rate-limit handling and real production-access verification.

Start by reading child issues #45–#48, then review the cross-cutting gates in this epic: read/write schemas, account isolation, support levels, protocol separation, schema drift, rate limits and production-access verification. Done means the connector programme and each child issue satisfy those gates, but this issue does not define a single newcomer-sized change.

Written by the indexing model from the issue text.