chore: remove tracked bytecode caches and gitignore them

[dholt]

Remove tracked Python bytecode caches and ignore them

What this is

The repository accidentally tracks compiled Python caches: run git ls-files | grep __pycache__ to enumerate them (expect four .pyc files under scripts/validation/). Remove them from version control with git rm -r --cached semantics by deleting the files from the working tree (the parent controller commits), and add __pycache__/ and *.py[cod] entries to the repository's .gitignore (create or extend it; keep existing entries intact). Touch nothing else. These files regenerate locally whenever the validation scripts run and cause spurious dirty-tree noise for every contributor and automation.

Verification

• Deterministic checks passed: diff check, no pycache in working tree, gitignore covers caches, public sanitizer, parent commit
• Two independent agent reviews approved head 52174b82f6e0 (different model vendors; strict verdict contract)
• Published by the DeepOps maintenance loop's deterministic publisher after its publication gate (reviews, provenance, exact-head) passed