Add bounded 1.0 stabilization gate

[ohmiler]

Summary

• preserve the verified v0.3.1 release/tag evidence on main
• add an offline, fail-closed 20-task stabilization gate with explicit Quick, Standard, and Critical criteria
• document the one-batch freeze policy and add schema, unit, and CLI regressions
• leave every runtime skill unchanged and exclude feedback/

Verification

• python -m pytest -q — 294 passed
• python scripts/validate_skill_suite.py — passed
• python -m solodeveling_protocol.cli . — passed
• empty field template returns insufficient-evidence with exit code 1
• git diff -- skills — no runtime skill changes

Limitations

• no real field observations or live model calls ran
• this does not authorize or create a version bump, tag, release, PyPI/npm publication, or comparative speed claim
• Tier 1 portability and unsigned native executable risks remain unchanged