roadmap: add Rust and Java dependency adapters

[mockingbird777]

Why

ArchLens already maps JavaScript, TypeScript, Python, and Go. Rust and Java are the next useful additions for polyglot service repositories.

Acceptance criteria

• Add analyzers behind the existing adapter boundary.
• Resolve local modules without executing project code.
• Include realistic fixtures and false-positive tests.
• Preserve zero runtime dependencies and relative-path-only reports.
• Document supported import forms and known limitations.

Focused proposals are welcome before implementation.