Implement resolveFromTypeRoot fallback in module resolution

[Copilot]

When typeRoots points to a non-ancestor directory (e.g. ../assets/node_modules/@types), imports of packages whose types live exclusively in those custom roots failed with TS2307: Cannot find module — even though tsc resolves them correctly.

Root cause

TypeScript's node-like module resolver falls back to resolveFromTypeRoot after exhausting node_modules traversal. In the Go port, this call was stubbed out:

if r.extensions&extensionsDeclaration != 0 {
    // !!!
    // if resolved := r.resolveFromTypeRoot(); !resolved.shouldContinueSearching() {
    //     return r.createResolvedModuleHandlingSymlink(resolved)
    // }
}

Changes

• internal/module/resolver.go — Implements resolveFromTypeRoot on resolutionState, mirroring the TypeScript original: iterates compilerOptions.TypeRoots, attempts loadModuleFromFile then loadNodeModuleFromDirectory with extensionsDeclaration, and attaches packageId from the nearest package.json. Only activates when TypeRoots is explicitly configured (not the default computed roots). Uncomments the call site in resolveNodeLikeWorker.

Baseline impact

Three compiler test baselines now match the TypeScript reference exactly:

Test	Before	After
moduleResolutionAsTypeReferenceDirective	TS2307 error, a2: any	no error, a2: number
moduleResolutionAsTypeReferenceDirectiveScoped	6 errors	3 errors (matches TS)
moduleResolutionAsTypeReferenceDirectiveAmbient	trace mismatch	trace matches TS