Remove benchmarks from repo, keep local only

Move benchmarks/ to .gitignore so the code stays on disk
for local runs but is never published to the repository.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: RecoDemo

.gitignore

@@ -58,8 +58,8 @@ htmlcov/
 # ── MCP local config ─────────────────────────
 .mcp.json
 
-# ── Benchmark results ────────────────────────────
-benchmarks/results/
+# ── Benchmarks (local only) ──────────────────────
+benchmarks/
 
 # ── Misc ───────────────────────────────────────
 *.log