Add RC1 regression benchmark artifacts

Add benchmark artifacts created during the first RC1 robustness evaluation of the Meeting Lab pipeline.

Included benchmark sets:

- hardware_experimental_qwen35_9b
- meeting_context_v1
- progeo_meeting_20260804_083849
- progeo_meeting_context_v1_20260804_110913
- progeo_meeting_rc1_20260804_121502

These artifacts document the evolution of the pipeline during the implementation
and verification of BUG-009, BUG-010 and BUG-011.

The benchmark data provide reproducible real-life regression cases for future
development and allow quality comparisons across pipeline revisions.

Current benchmark policy:

During the active development phase, representative benchmark artifacts are
intentionally versioned to preserve reproducibility and simplify regression
analysis.

Benchmark artifacts are considered part of the engineering evidence rather than
temporary build output. Benchmark retention strategy will be revisited once the
Meeting Assistant reaches production maturity.

samples/benchmarks/progeo_meeting_context_v1_20260804_110913/timings.json

@@ -0,0 +1,12 @@
+{
+    "chunking_seconds":  0.133,
+    "normalization_seconds":  0.739,
+    "chunk_count":  10,
+    "total_started_marker_seconds":  0.91,
+    "extraction_seconds":  255.876,
+    "extraction_exit_code":  0,
+    "canonicalizer_seconds":  0.162,
+    "canonicalizer_exit_code":  0,
+    "consolidator_seconds":  61.716,
+    "consolidator_exit_code":  1
+}