[TASK] Build connector API-validation harness (fan-out: manifest vs live vendor API)

[AtelyPham]

Part of tangle-network/agent-dev-container#1898

Problem

136 OAuth2 + ~400 api-key connectors. One-by-one QA ≈ 400 days. Need an automated validation pass.

Build

A fan-out harness (dynamic workflow, ~1 validator per connector) that checks each adapter's manifest against the live vendor API:

• base URL reachable; auth kind correct
• OAuth: authorize/token URLs, scopes, token refresh, extra auth params
• endpoints: path / method / params / pagination vs vendor docs/OpenAPI
• 2–3 representative tool calls execute where a test cred exists

Emits a structured result per connector (pass / warn / fail + reason), consumed by the validation-findings checklist (filed alongside this issue).

Acceptance

• Runs over the full connector set; machine-readable output + a human checklist.
• Piloted on the ~21 already-registered providers with results attached.