feat: sync missing features from v0.49.x line to master

The v0.49.x tag line diverged from origin/master, leaving many
features only accessible via tags but not on the master branch.

New modules:
- ci/cancel_superseded_runs.py — cancel superseded CI runs
- ci/check_workflow_artifact_deps.py — validate artifact deps
- ci/check_workflow_tofu_init.py — validate tofu init steps
- tools/check_alert_rules.py — validate Prometheus alert rules
- tools/check_ansible_set_fact_to_json.py — lint set_fact usage
- tools/check_docker_init.py — validate Docker init scripts
- utils/jinja.py — Jinja2 template utilities
- utils/ui.py — UI/console utilities

Modified modules:
- distribute_molecule.py: add --include-roles/--exclude-roles
- utils/api.py: add container.credentials for private registry auth
- install_tools.py: retry ansible-galaxy on transient timeouts
- setup_image.py: skip dep resolution with --no-deps
- cli.py: register new commands
- i18n.py: add new translation keys

Also removes accidentally committed .vale/styles/Google/ files.

Test results: 2195 passed, 100% coverage.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

docs/retrospectives/2026-07-12-self-approval-fallback-and-ci-consolidation.md

@@ -132,7 +132,7 @@ unblocked auto-merge across all three repos.
 ### 2. Double-Prefix Detection (MEDIUM impact)
 
 `check_auto_merge_ready.py` now detects and rejects Vikunja task titles
-that include the identifier prefix (for example, "DEVX-127: Fix...").
+that include the identifier prefix (for example, "DEVX-127: Fix").
 The validator adds the prefix automatically, so a double prefix would
 fail validation.