enhancement

[edouardmisset]

Depends on: #23

What to build

Add validation that each workspace provides a fixtures.ts with the required FixtureFactory interface. Benchmark startup fails with clear error if any workspace is missing it.

Acceptance criteria

• On deno task bench startup, scan each workspace for fixtures.ts
• Load and validate FixtureFactory interface: { small(), medium(), large() }
• Fail with error message if any workspace is missing fixtures.ts
• Error message lists affected workspaces and expected file path
• Prevents silent gaps in benchmark coverage

Out of scope

• Automatic fixture generation