fix(aidp): support legacy and new model APIs

[cj2026-bit]

Summary

• Support both AIDP model-list endpoint contracts: legacy Service and new Query.
• Probe both endpoints once on cold start, prefer Service when both are non-404, and cache SERVICE/QUERY in process memory.
• Translate version-specific query parameters and normalize wrapped-object and direct-array responses while preserving the backend API contract.
• Update the local AIDP mock server and add compatibility, retry, cache, response, and error tests.

Validation

• pytest test/ext_components/aidp -q: 510 passed
• Local mock verified both endpoint modes and backend model filtering.
• Full project test entrypoint generated coverage (88% overall) but had unrelated baseline/environment failures outside the changed files.

Issue association: none.

[codecov]

Codecov Report

❌ Patch coverage is 91.54930% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ckend/ext_components/aidp/services/aidp_service.py	91.54%	5 Missing and 1 partial ⚠️

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