Rust-native rootDirs inherited config completion

[jununfly]

This was generated by AI during triage.

Parent

• Roadmap plan: docs/plans/2026-06-22-rust-native-typescript-module-resolution-roadmap.md
• Config interpretation plan: docs/plans/2026-06-22-rust-native-config-interpretation-completion.md
• Roadmap node: 1-2-5. rootDirs

What to build

Complete the bounded Rust-native rootDirs config interpretation slice for repo-local relative import parity. When a source file is under any configured rootDir, relative imports should be able to target the same virtual-relative path under another rootDir. This must work when rootDirs comes from a repo-local inherited config and each rootDir path must be interpreted relative to the config file that declared it.

The goal is rootDirs parity for repo-local file-level moduleResolution, not TypeScript compiler completeness for every rootDirs-related emit/declaration behavior.

Acceptance criteria

• Relative imports from one rootDir can resolve to the same virtual-relative path in another rootDir.
• Inherited rootDirs preserve the declaring config file path basis from the merged config model.
• Diagnostics/profile taxonomy distinguishes rootDirs resolved, target-not-found, and config-out-of-scope outcomes.
• Deterministic Rust fixtures cover direct rootDirs, inherited rootDirs, target-not-found, and a non-rootDirs source file that should not use virtual root lookup.
• Existing baseUrl/paths, package maps, and explicit extension pairing behavior is not regressed.

Blocked by

• Rust-native moduleResolution repo-local config extends/default handling #447

[jununfly]

This was generated by AI during triage.

Closing as implemented. Rust-native rootDirs now covers inherited config path basis and reports rootDirs target-not-found vs config-out-of-scope taxonomy for repo-local relative import parity.

Evidence:

• cargo test -p zcodegraph-core
• closeout: docs/benchmarks/2026-06-22-config-interpretation-closeout.md