Release Compass 0.4.0

[forhappy]

Summary

• Bump Compass workspace, internal dependency, lockfile, and VS Code extension metadata to 0.4.0.
• Move the accumulated unreleased changelog entries under the dated 0.4.0 heading.
• Update the qualification fixture producer version.

Release highlights

• Improve source-backed navigation, owner-qualified queries, and explanations while preserving ambiguity and bounded results.
• Add clearer evidence and bounded reporting for architecture summaries, hubs, and directed trails.
• Refine Go, Java, and Rust relationship evidence and detect same-size source replacements in graph caches.
• Improve viewer spacing, responsive controls, appearance settings, and deterministic initial positioning.

See the 0.4.0 changelog and compare with 0.3.30.

Validation

• cargo metadata --no-deps --locked and uniform workspace version audit
• cargo check --workspace --all-targets --locked
• cargo fmt --all -- --check
• cargo clippy --workspace --lib --bins --locked -- -D warnings
• cargo test --workspace --lib --bins --locked
• cargo test -p compass-cli --test compass_product --locked
• sh scripts/check_product_boundary.sh
• sh scripts/test_release_scripts.sh
• ./scripts/qualify_code_graph_v1.sh --fixtures-only
• npm ci, npm run typecheck:js, npm run test:js, and node scripts/check_viewer_assets.mjs