Add Polyfill Layer Two Stream Coverage

add-polyfill-connector-system has become a mixture of shipped MVP infrastructure, live connector bug notes, and a large Layer 2 stream backlog. That makes it hard for workers to improve connector coverage without touching unrelated runtime or governance work.

Improve the first-party polyfill fleet's usefulness while preserving provenance honesty. This change is not about making every connector broad; it is about adding streams that materially improve assistant/demo value and can be verified against real owner data or clearly marked unavailable.

The reference implementation SHALL distinguish verified owner-account connector data from seed, fixture, demo, scaffolded, or blocked connector data when using first-party polyfill connectors as evidence of reference behavior.