TX Austin-Travis ingestion execution

[thefiredev-cloud]

Context

TX ingestion plan landed in 4e4f799 (PR #48). Execute Austin-Travis County EMS ingestion per plan.

Acceptance criteria

• Austin-Travis protocols acquired
• Cleaned, chunked, embedded via Voyage AI
• Loaded into manus_protocol_chunks with correct agency_id
• Retrieval eval regression passes on Austin-Travis sample queries
• Coverage metrics reported in dashboard

Blocker

None.

Related planning docs

• docs/plans/ingestion-tx-austin-travis.md