fix(workout-builder): require all inferred exercise equipment

[evan188199-tech]

Summary

• Infer hidden equipment requirements from exercise names and instructions (bench/chair/step/box/desk surfaces, suspension work, pull-up-bar hanging, and towel resistance).
• Keep multiple EQUIPMENT tags during CSV import and filter exercises using all required tags, not just any matching tag.
• Add an idempotent, add-only backfill script that defaults to dry run and writes only with --apply.
• Add Vitest coverage for equipment inference and all-requirements selection semantics.

Why

Some exercises are tagged only with their primary equipment even though their instructions require another item. For example, a dumbbell bench press can still appear for a dumbbell-only selection because the current query treats multiple equipment tags as an OR match.

Safety

The backfill only appends missing inferred tags and never removes existing tags. The importer drops stale BODY_ONLY from the resolved equipment set only when another material requirement was inferred, so pure bodyweight movements remain unchanged.

Tests

• pnpm install --frozen-lockfile
• pnpm test
• pnpm exec tsc --noEmit
• Targeted ESLint check
• git diff --check

[vercel]

Someone is attempting to deploy a commit to the Workoutcool Team Team on Vercel.

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[evan188199-tech]

@Snouzy Could you please approve the fork workflow run and take a look when you have a chance? The branch is rebased on the latest main, and local pnpm test, pnpm exec tsc --noEmit, targeted ESLint, and git diff --check all pass.