Follow tsconfig.json extends + project-relative node IDs for JS/TS

[ghaiat-yoobic]

Builds on #155 (by @nuthalapativarun) which added compilerOptions.paths resolution. Three issues that surface on a real-world Nx/Angular monorepo (~7,725 TS files):

1. extends chains are ignored

Every project tsconfig in Nx/Angular monorepos typically looks like:

{ "extends": "../../tsconfig.base.json" }

with no paths of its own — all aliases live in the shared base file. The previous implementation returned an empty alias map for these files, so every alias-style import silently fell back to basename matching.

Fix: load_tsconfig_paths is refactored into a recursive helper that walks the extends chain. Each level's own paths override anything inherited; paths defined in a base file resolve relative to that base file's directory, matching TypeScript's behaviour.

2. Node IDs collapse on basename

Even with alias resolution working, every node ID was derived from path.stem (filename without extension). Across a 7,725-file project we found:

target id	edges before	what it actually was
data	2,003	every test/data.ts file
base	1,394	several base.tsx components
text	765	many text.tsx components

All those files collapsed onto a single node.

Fix: new optional LanguageConfig.id_for_path callable. When set, _extract_generic rebinds stem to its return value before deriving file/class/function/method IDs. extract_js computes the project root via find_project_root (new helper that walks up looking for .git) and passes a closure that returns the project-relative stem.

_import_js takes a matching project_root kwarg. When the resolved import path is absolute (via alias resolution) or relative (./, ../), it derives the target ID the same way — so source-file IDs and import-target IDs always agree.

3. Directory-style imports point at phantom nodes

Resolving @yobi/layout/flex to /.../src/flex and then computing a node ID misses that the actual file is flex/index.ts. The file extractor emits src_flex_index; the import resolver emits src_flex. Edge points at a phantom.

Fix: new _resolve_module_file helper — tries the path as-is, then with .ts/.tsx/.d.ts/.js/.jsx/.mjs/.cjs, then as a directory with index.{ts,tsx,js,...}. Import handler uses the resolved file path (when found) to derive the target ID. Falls back to the un-resolved path if nothing on disk matches, so broken imports still get a stable ID.

Backwards-compat & scope

• External imports (npm packages like rxjs, @angular/core) and unresolved aliases continue to use the legacy basename behaviour.
• The basename-collision fix is JS/TS only via the optional id_for_path field — Python/Java/Go/etc. extractors are untouched. Same fix could be applied per-language in follow-ups.
• The extends-walking change in load_tsconfig_paths is contained — empty-paths case still returns {}.

Measured impact on the test corpus

Same 7,725-file Nx/Angular repo, before and after, holding everything else constant:

	imports → real in-repo file nodes
PR #155 alone	~0 (extends never resolved)
+ extends fix	3,737
+ project-relative IDs	(path collisions resolved but phantom directory targets)
+ module file resolution	20,890

Note on the head commit / split

This branch carries the 3 PR #155 commits at the base. Once #155 merges, this can be rebased to drop them. Happy to split into separate PRs — the three commits here are independent and could each land on their own.