#535 [API/Perf] version.py subprocess in async endpoint without caching

File: api/blueprints/v1/version.py:21-48. subprocess.run for git commands runs synchronously in async endpoint. Called on EVERY request. capture_output=True captures ALL output into memory. IMPACT: Blocks event loop, potential memory issues with malicious .git. FIX: Cache git info at startup, not per-request.