[business_analysis] Implement all third party integrations in Lovable

_Automatically composed from the parent epic at dispatch time._

PRD settled: Lovable-parity integrations, covering the shared catalog (~110), 18 chat MCP connectors, and custom REST/MCP. Each gets Connect, a test, runner use and docs, on one generic framework. Jaah OAuth apps allow BYO. Delivery is in waves. Human registration tasks are filed per wave, and builds settle on unit tests without waiting for them. App-user connectors and Managed-by-Jaah are out of scope. Memory: none applied.