[sasan1200]

• catalog.json / .claude-plugin/marketplace.json / README: add harness (cavi-ai/harness, claude host only)
• catalog.schema.json + validate-catalog.mjs: plugins minItems 1 (no max); hosts minItems 1; packages required only for declared hosts; packages for undeclared hosts rejected; name enum gains harness
• tests: claude-only plugin accepted, wide projection of a claude-only plugin rejected, undeclared-host package rejected; 41/41 pass; validate-catalog passes

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