Pass Odoo overrides into stable bootstrap

[cbusillo]

Summary

• read the Odoo instance override record before stable bootstrap scheduling
• pass the encoded override payload and required env keys into the bootstrap data workflow
• add regression coverage proving stable bootstrap forwards ODOO_INSTANCE_OVERRIDES_PAYLOAD_B64

Context

Follow-up from cbusillo/odoo-devkit#34 live verification after #590 landed. Target replacement successfully advanced CM testing to artifact-cm-d86025a089905522 / ff348ec8df2de651e4d1a36a62e6c134374b4531, but stable bootstrap still left the public page as My Website with canonical http://localhost:8069/cell-mechanic.

Root cause: post-deploy passed Odoo override environment into the data workflow, but stable bootstrap did not. That meant devkit's website_bootstrap payload was never available to apply_website_bootstrap during the bootstrap schedule.

Tests

• uv run python -m unittest tests.test_odoo_stable_bootstrap
• uv run --extra dev ruff check --diff control_plane/workflows/odoo_stable_bootstrap.py tests/test_odoo_stable_bootstrap.py
• uv run --extra dev ruff check control_plane/workflows/odoo_stable_bootstrap.py tests/test_odoo_stable_bootstrap.py