refactor(ide): centralize semantic target resolution

[hongjr03]

Summary

• Introduce shared semantic target resolution state for source, preprocessor macro, and include targets.
• Route hover, navigation, references, highlights, and rename through intent-based projections.
• Model ambiguous preprocessor source targets as alternatives for hover/navigation while keeping rename, references, and highlights unique-target only.

Validation

• cargo fmt --check
• git diff --check
• cargo check -p ide
• cargo test -p ide --lib

[github-actions]

Docs preview: https://vide.pascal-lab.net/preview/pr-281/