Fix call artifact identity resolution

[dionysuzx]

Summary

• resolve asset pipeline targets from mapped call identity before downloading, summarizing, or publishing artifacts
• remove the unsafe Zoom date/topic fallback that could ingest a recording from another series
• fail on ambiguous call numbers or same-day recordings instead of guessing
• reject numbered artifact directories that do not match a mapped occurrence during manifest generation
• remove the invalid P2P artifact and orphan PQ Interop artifacts generated by the previous fallback

Why

The pipeline treated date plus inferred topic prefix as enough to recover from missing Zoom mappings. That made an incorrect recording look valid and allowed it into the manifest.

The pipeline now requires a mapped occurrence identity for numbered artifacts and uses existing artifact directories only after the target call is known.

Validation

• .github/ACDbot/.venv/bin/python -m pytest .github/ACDbot/tests
• .github/ACDbot/.venv/bin/python .github/ACDbot/scripts/asset_pipeline/generate_manifest.py
• GitHub checks passed: validate, GitGuardian Security Checks