Align Python provider contracts

[GTrunSec]

Summary

• align provider doctor, workspace-scope, query-pack, and invocation contracts
• keep semantic language registry and owner-item evidence on schema v1
• remove legacy direct-read projection tests and add structural-selector/provider-doctor coverage
• sync semantic-structural-index.v1 with the shared ASP schema extension

Verification

• uv run --frozen --group test python -m pytest -o addopts= tests (376 passed on the earlier aligned snapshot)
• uv run --frozen py-harness check --full .
• root ASP profile-copy + structural-index gate passed
• latest CI formatting and lint pass; provider test baseline remains red
• pre-commit ruff and ruff-format passed