Add generic web post-deploy extension hook

[shiny-code-bot]

Summary

• add an opt-in generic-web post-deploy extension hook with typed context and terminal evidence validation
• carry post-deploy status through generic deploy/rollback results without confusing provider deploy status with product maintenance status
• document the inheritance boundary so Odoo rollback apply stays product-owned until release tuple, backup, runtime safety, and post-deploy invariants are represented safely

Validation

• uv run python -m unittest tests.test_generic_web_deploy tests.test_generic_web_rollback tests.test_generic_web_promotion tests.test_service
• uv run --extra dev ruff check --diff control_plane/workflows/generic_web_deploy.py control_plane/workflows/generic_web_rollback.py tests/test_generic_web_deploy.py tests/test_generic_web_rollback.py
• uv run --extra dev ruff check control_plane/workflows/generic_web_deploy.py control_plane/workflows/generic_web_rollback.py tests/test_generic_web_deploy.py tests/test_generic_web_rollback.py
• uv run --extra dev ruff format --check control_plane/workflows/generic_web_deploy.py control_plane/workflows/generic_web_rollback.py tests/test_generic_web_deploy.py tests/test_generic_web_rollback.py
• uv run --extra dev mypy control_plane tests
• uv run python -m unittest

Notes

• JetBrains changed-files inspection helper returned STATUS: error without findings before PR creation, so this is recorded as a tool failure rather than a code finding.
• Agent validation agreed this should be a structural hook only; Odoo apply should not move onto generic deploy yet.