Run 10k MPL Regression Test and Document Results

[pt2710]

Action: Execute regression test suite (10,000 primes) locally and document results in issue thread.

Steps:

1. Run pytest tests/test_regression_against_reference.py -s
2. Capture:
   • Pass/fail status
   • MPL runtime
   • Reference runtime
   • Speed ratio
3. Confirm structural invariant: only one odd gap (2→3)
4. Post console output in this thread.

Purpose: Formal closure of MPL structural validation (v1.1).