docs: Add mandatory testing rule to CLAUDE.md

- Added critical rule requiring ephemeral instance testing after every task
- Specified exact commands to run for testing
- Emphasized checking logs for errors before proceeding

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

CLAUDE.md

@@ -30,6 +30,14 @@ docker-compose down -v
 ### Instance Persistence Policy
 After successful installation/update, the instance must remain active for user validation. Do NOT stop the instance until user explicitly confirms testing is complete.
 
+### MANDATORY Testing Rule
+**CRITICAL**: After EVERY task that modifies code, models, views, or data:
+1. Restart the ephemeral instance: `docker-compose down -v && docker-compose up -d`
+2. Check initialization logs for errors: `docker-compose logs odoo_init | grep -i "error\|traceback\|exception"`
+3. Verify successful completion: `docker-compose logs odoo_init | tail -30`
+4. Only proceed to next task if no errors are found
+5. If errors are found, fix them before continuing
+
 ### Database Operations
 
 #### Direct PostgreSQL Access