docs: map existing codebase with PAUL

- stack.md - PrestaShop 1.7.x, PHP, Smarty, SCSS, modules
- architecture.md - MVC + hooks, override mechanism, CQRS in src/
- structure.md - Directory layout, key file locations
- conventions.md - PHP/Smarty/SCSS/JS conventions, PS patterns
- testing.md - No automated tests in custom modules
- integrations.md - Allegro, Empik, BaseLinker, shipping, payments
- concerns.md - Override fragility, EOL risk, missing CI/CD
- db_schema.md - Custom tables, modified core tables

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

.paul/codebase/testing.md

@@ -0,0 +1,67 @@
+# Testing Patterns
+
+**Analysis Date:** 2026-04-27
+
+## Test Framework
+
+**Runner:** None — no unit/integration test framework in custom modules
+
+**Static Analysis:**
+- PHPStan (level 5) present only in `modules/blockreassurance/tests/php/phpstan/phpstan.neon`
+- Not configured for custom modules (`customfeaturetab`, `AddOrderExtraFields`)
+
+**Run Commands:**
+```bash
+# No test commands defined
+# Only available for blockreassurance (pre-installed PS module):
+# modules/blockreassurance/tests/php/phpstan/
+```
+
+## Test File Organization
+
+**Custom modules — no tests found:**
+- `modules/customfeaturetab/` — no tests directory
+- `modules/AddOrderExtraFields/` — no tests directory
+- `modules/addcolumninlist/` — no tests directory
+
+**Pre-installed modules with static analysis only:**
+- `modules/blockreassurance/tests/php/phpstan/` — PHPStan config only
+
+**Core PrestaShop:**
+- `classes/ConfigurationTest.php` — system configuration checker (not unit tests)
+
+## Coverage
+
+**Requirements:** None enforced
+
+**Current state:** No automated test coverage for custom code
+
+## Testing Approach in This Project
+
+Since there is no automated test suite, verification is done manually:
+
+1. **Deploy to production via FTP** (`.vscode/ftp-kr.json`)
+2. **Clear PrestaShop cache** — Admin → Advanced Parameters → Performance
+3. **Manual browser testing** of affected pages
+4. **Check admin panel** for errors after module changes
+
+## Recommendations for Adding Tests
+
+If implementing tests in the future:
+
+**For PHP modules:**
+- PHPUnit 9.x (compatible with PHP 7.x)
+- Composer dev dependency in module
+- Test location: `modules/{name}/tests/`
+
+**For static analysis:**
+- PHPStan level 5+ with PrestaShop stubs
+- Config: `modules/{name}/phpstan.neon`
+
+**For Smarty templates:**
+- Manual verification only (no template test framework)
+
+---
+
+*Testing analysis: 2026-04-27*
+*Update when test patterns change*