Scans every src/**/*.svelte.{spec,test}.ts file for vi.mock first-arg
strings, canonicalises each by stripping a trailing .js/.ts after
.svelte, groups by canonical id, and fails if any canonical id is
referenced under two or more distinct raw spellings.
Mirrors the shape of src/__meta__/no-async-mock-factories.test.ts:
source-text regex scan (no AST parser dependency), red/green self-test
fixtures inline, then one corpus assertion that the whole suite is
clean.
This is the in-suite defence-in-depth layer for the duplicate-id birpc
race named in ADR-012 / #553 and fixed upstream by vitest PR #10267.
Harder to disable than ESLint (cross-file invariant ESLint cannot
express anyway) and harder to scope around than a CI grep.
Refs: #553
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>