fix(scanner): Resolve Rust workspace imports

[reneleonhardt]

What does this PR do?

• Resolve mod declarations only within their legal Rust module tree.
• Resolve fully-qualified crate calls from Cargo workspace membership and package names.
• Report partial coverage when dynamic routes cannot be inferred.
• Verify a known cross-layer dependency after Codemap tuning.

Type of change

• Bug fix
• New feature
• New language support
• Documentation
• Other

Verification

• go test ./scanner -run '^TestRustWorkspace' -count=1

Developed with carefully directed, manually reviewed AI assistance.

Co-Authored-By: GPT-5.6 Sol codex@openai.com

[JordanCoin]

Heads up for sequencing: #84 and #85 just landed on main, and #86 will need a merge-up/rebase against them (details in the comment there) before this one. Expect scanner/filegraph.go and the scanner tests to have moved underneath this branch — probably worth rebasing this after #86 settles rather than before. No review concerns from a first read of the Rust module-tree/Cargo-membership approach; will do a full review once it's rebased.

[reneleonhardt]

Rebased onto current main without problems.
The reconciliation retains main’s scanner graph contracts alongside the Rust module-tree and Cargo-workspace resolution.
The focused Rust and scanner truth tests, full race-and-coverage suite, vet, staticcheck, build, and --deps smoke test are green.
Ready for full review.