Add review skill and make review stage mandatory in AGENTS.md

- Add .agents/skills/review/SKILL.md with a required review checklist covering
  project rules, model client rules, pipeline rules, XML rules, and test rules.
- Update AGENTS.md with a dedicated 'Review Stage Rules' section that makes
  review mandatory and maps confidence thresholds to XML generation behavior.
- Add review skill to the skills reference.
- Add .ruff_cache/ to .gitignore and keep agent XML templates out of the '*.xml' ignore rule.

.gitignore

@@ -47,6 +47,7 @@ dmypy.json
 htmlcov/
 .tox/
 .nox/
+.ruff_cache/
 
 # Project-specific
 out/
@@ -54,5 +55,6 @@ output/
 *.xml
 !tests/fixtures/*.xml
 !templates/*.xml
+!src/odoo_ocr/.agents/skills/odoo-xml-import/templates/*.xml
 .cache/
 ~/.cache/