Add public adaptation package

[FransDevelopment]

Summary

• add PUBLIC_ADAPTATION_GUIDE.md as a self-serve aggregate-only adaptation path for public-health partners
• add grounded examples derived from the current public BDBV snapshot, public health-zone counts, public source manifest, and public calibration ledger
• link the adaptation package from README and READONLY_INTERFACE_PUBLIC.md and include it in release_manifest hashing
• add tests that parse the examples, verify they match the public source artifacts, and reject protected-field markers

Validation

• public export artifacts current
• public repository hygiene clean
• public tests pass
• Python compile check passes
• whitespace diff check passes

Boundary

This adds public-good adaptation docs and already-public aggregate examples only. It does not publish the LOVS model runner, source collection automation, private-data adapters, mutable resolver/scoring tools, probability intervals, feature weights, or model parameters.