feat(parser): resolve TypeScript path aliases in IMPORTS_FROM edges

[JF10R]

Summary

• Add TsconfigResolver class that discovers and parses tsconfig.json files (with JSONC comment support and recursive extends resolution)
• Resolve TypeScript path aliases (e.g., @/* → src/*) declared in compilerOptions.paths to absolute file paths
• IMPORTS_FROM edge targets are now resolved when the target file exists on disk, enabling importers_of() queries to work with alias imports

Before: importers_of('src/hooks/useApiData.ts') returned 0 results despite 28 files importing it via @/hooks/useApiData
After: Returns all 28 importers correctly

Changes

• New file: code_review_graph/tsconfig_resolver.py — TsconfigResolver class with tsconfig discovery, JSONC parsing, extends chain resolution, path alias matching, and filesystem probing
• Modified: code_review_graph/parser.py — integrated resolver into _do_resolve_module() for non-relative imports and _extract_from_tree() for IMPORTS_FROM edge resolution
• New tests: tests/test_tsconfig_resolver.py (7 unit tests) + 2 integration tests in test_parser.py
• New fixtures: tsconfig.json, src/lib/utils.ts, alias_importer.ts

Design decisions

• Resolution only replaces raw import strings when the target file exists on disk — npm packages and unresolvable aliases remain as-is
• tsconfig is cached per directory (all files in the same project share one entry)
• Supports extends chains with cycle detection; skips npm-scoped extends (e.g., @tsconfig/recommended)

Test plan

• All 37 parser + resolver tests pass (pytest tests/test_parser.py tests/test_tsconfig_resolver.py -v)
• Full test suite: 196 passed, 26 pre-existing Windows-only SQLite teardown errors
• Validated on a real-world TypeScript project (357 files): importers_of() returns correct results for alias-imported files

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds TypeScript tsconfig.json path-alias awareness to the graph parser so IMPORTS_FROM edges can resolve alias imports (e.g., @/…) to real on-disk files, enabling accurate importers_of() queries in TS/TSX/Vue projects.

Changes:

• Introduces TsconfigResolver to discover/parse tsconfig.json (JSONC + extends) and resolve compilerOptions.paths aliases to existing files.
• Integrates alias resolution into CodeParser module resolution and IMPORTS_FROM edge extraction.
• Adds unit/integration tests and fixtures to validate alias resolution and no-tsconfig behavior.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
code_review_graph/tsconfig_resolver.py	New resolver for tsconfig discovery, parsing, extends resolution, and alias-to-file probing.
code_review_graph/parser.py	Uses resolver during module resolution and updates IMPORTS_FROM edges to prefer resolved file paths.
tests/test_tsconfig_resolver.py	Unit tests for JSONC stripping, alias resolution, and caching behavior.
tests/test_parser.py	Integration tests ensuring alias imports resolve and missing tsconfig doesn’t break parsing.
tests/fixtures/tsconfig.json	Fixture tsconfig defining baseUrl and paths aliases used by tests.
tests/fixtures/src/lib/utils.ts	Fixture target file for alias resolution.
tests/fixtures/alias_importer.ts	Fixture importer using @/… alias.

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[JF10R]

All 9 review comments addressed in 9093057:

tsconfig_resolver.py:

• JSONC comment stripping rewritten as state machine (no longer corrupts URLs in strings)
• _load_tsconfig_for_file() now caches all visited directories during walk-up
• Docstring corrected: "deep-merges" to "shallow-merges" to match dict.update() behavior
• Path alias patterns sorted by specificity (longest non-wildcard prefix first)
• _probe_path() appends extensions when base already has a suffix instead of replacing

Tests:

• Split import tempfile, os (Ruff E401)
• Long assert line extracted into separate error_msg variable
• Both test files use TemporaryDirectory for isolation instead of hardcoded paths

[tirth8205]

Integrated into main via PR #68. Thank you for the contribution! 🎉