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/db_schema.md

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+# Database Schema
+
+**Analysis Date:** 2026-04-27
+
+## Connection
+
+- Host: `dedyk75.cyber-folks.pl`
+- Database: `interblue_sklep`
+- Table prefix: `ps_`
+- Engine: InnoDB
+- Charset: UTF-8 (note: custom tables use `utf8` not `utf8mb4`)
+- Cache: Memcached
+
+## Core PrestaShop Tables (selected)
+
+Standard PrestaShop tables present (not listed exhaustively — see PS docs):
+- `ps_orders` — Orders (modified by AddOrderExtraFields, see below)
+- `ps_order_history` — Order status history
+- `ps_order_invoice` — Invoices
+- `ps_order_payment` — Payment records (modified by AddOrderExtraFields)
+- `ps_product` — Products
+- `ps_product_lang` — Product translations
+- `ps_cart` — Shopping carts
+- `ps_customer` — Customers
+
+## Custom Tables (Added by Modules)
+
+### `ps_custom_feature_tab` — Feature Tab Rules
+Created by: `modules/customfeaturetab/customfeaturetab.php`
+
+| Column | Type | Notes |
+|--------|------|-------|
+| id_custom_feature_tab | INT UNSIGNED | PRIMARY KEY, AUTO_INCREMENT |
+| id_feature | INT UNSIGNED | Feature ID from ps_feature |
+| id_feature_value | INT UNSIGNED | Feature value ID |
+| position | INT UNSIGNED | Display order |
+| active | TINYINT(1) | Enable/disable |
+| date_add | DATETIME | |
+| date_upd | DATETIME | |
+
+### `ps_custom_feature_tab_lang` — Feature Tab Content (Multilang)
+Created by: `modules/customfeaturetab/customfeaturetab.php`
+
+| Column | Type | Notes |
+|--------|------|-------|
+| id_custom_feature_tab | INT UNSIGNED | FK → ps_custom_feature_tab |
+| id_lang | INT UNSIGNED | FK → ps_lang |
+| title | VARCHAR(255) | Tab title |
+| content | TEXT | Tab HTML content |
+
+Primary key: (id_custom_feature_tab, id_lang)
+
+## Modified Core Tables (by Modules)
+
+### `ps_orders` — Order Source Field
+Added by: `modules/AddOrderExtraFields/AddOrderExtraFields.php`
+
+| Column | Type | Notes |
+|--------|------|-------|
+| order_source | ENUM('Allegro', 'Sklep int.', 'Telefonicznie') | Added via ALTER TABLE |
+
+Logic: Set in `modules/AddOrderExtraFields/override/classes/PaymentModule.php`
+- 'Allegro' — when `$order->module == 'x13allegro'`
+- 'Sklep int.' — default for web store orders
+- 'Telefonicznie' — manual phone orders (set manually in admin)
+
+### `ps_order_payment` — Card Payment Field
+Added by: `override/classes/order/OrderPayment.php`
+- Additional field for storing card payment type (max 254 chars)
+
+## Migration Approach
+
+- No migration framework — DDL executed in module `install()` methods
+- ALTER TABLE statements in `AddOrderExtraFields.php`
+- CREATE TABLE in `customfeaturetab.php`
+- No rollback scripts (uninstall drops custom tables)
+- No version tracking for schema changes
+
+## Known Issues
+
+- Custom tables use `utf8` charset (should be `utf8mb4` for full Unicode/emoji support)
+- `ps_custom_feature_tab` has no index on `id_feature` or `id_feature_value` (potential slow queries on large catalogs)
+- `order_source` enum requires ALTER TABLE to add new order sources
+
+---
+
+*DB schema: 2026-04-27*
+*Update when modules add/modify tables*