Release Compass 0.3.12

[forhappy]

Summary

• Bump Compass workspace, internal package constraints, locks, qualification producer, and VS Code extension to 0.3.12.
• Promote the 0.3.12 changelog entries covering large graph stores, universal-evidence resilience, Markdown resolution, and Python/TypeScript discovery.

Release notes

• Remove the aggregate canonical-payload limit from current SQLite graph-index snapshots while retaining bounded objects, batches, scans, and queries.
• Prevent oversized universal-evidence collections from collapsing graphs; preserve useful partial graphs with explicit omission diagnostics.
• Improve Markdown document identity and exact link resolution, including headings, repository roots, directory indexes, and unique wikilinks.
• Improve natural Python and TypeScript discovery ranking and framework compatibility propagation, with pinned HTTPX/NestJS relevance oracles.

Validation

• cargo check --workspace --all-targets --locked
• cargo fmt --all -- --check
• cargo clippy --workspace --lib --bins --locked -- -D warnings
• cargo test --workspace --lib --bins --locked
• Compass product contract, product boundary, release-script, and fixture-only code-graph qualification gates
• npm ci, JavaScript typecheck/tests, browser tests, and deterministic viewer-asset check

This PR is the exact source for the annotated compass-v0.3.12 tag after merge.