feat: add deploy automation reusables

[jorisjonkers-dev-agents]

Summary

• Adds reusable deploy-v2 bundle and deployment source render workflows with matching composite actions.
• Adds reusable Project build(deps): bump actions/checkout from 6 to 7 #2 auto-add and repository hygiene guard workflows.
• Applies shared CI warning fixes for stale action majors, generated npm auth, and generated-client Javadoc doclint noise.
• Applies repository hygiene: canonical proprietary license, lean README, CODEOWNERS owner, .gitattributes/.gitignore hardening, and removal of the listed .specify/ and specs/00x-* planning leftovers.

Skipped

• publish-api-clients.yml keeps openapi-client-gradle-version at 0.3.0 because openapi-client-gradle has no published tag newer than v0.3.0 yet.

Validation

• /tmp/actionlint -ignore 'property "job_workflow_sha" is not defined' .github/workflows/*.yml
• python3 -m unittest discover -s tests
• python3 -m coverage run --source=scripts.check_migrations -m unittest discover -s tests
• python3 -m coverage report --fail-under=80 (91%)
• bash -n actions/deploy-bundle/run.sh actions/deploy-sources-render/run.sh actions/api-client-publish/run.sh actions/platform-config-validate/run.sh actions/deploy-config-render-drift/run.sh
• git diff --cached --check