Remove hosted runtime authority from devkit stack

[cbusillo]

Summary

• remove CM/OPW hosted runtime values from the checked-in devkit stack while preserving local DX and hosted module intent
• require Launchplane's explicit runtime-environment payload for non-local artifact publishing and make it authoritative over stack values
• fail closed on malformed or incomplete payloads, including missing Odoo version
• update runtime docs and regression coverage

Validation

• uv run python -m unittest discover -s tests (160 passed, 1 skipped)
• uv run ruff check .
• uv run ruff format --check .
• uv build
• uv run platform --help

Refs cbusillo/launchplane#1618