Support source=codewith across API CLI SDK sync and watch

[andrei-hasna]

Problem

The parser alone is insufficient: cloud validators, OpenAPI, SDKs, CLI filters/help, sync, watch, daemon, and MCP source lists reject or omit codewith.

Acceptance

• All public source enums include codewith.
• Local ingest and self-hosted dry-run/live sync accept codewith.
• CLI filtering, help, watch status, daemon status, and SDK types agree.
• Unknown sources fail consistently.
• Contract tests cover local and cloud modes.

Related: #10
Todo: OPE2-00076