docs: Added Docs for Normalizer.

Author: N3XT0R

docs/usage.md

@@ -40,6 +40,76 @@ Schema::create('users', function (Blueprint $table) {
 });
 ```
 
+## Schema Normalization
+
+### Motivation
+
+Legacy database schemas often use **composite primary keys**, which are **not supported** by Laravel's Eloquent ORM.
+This can cause issues when working with relationships, factories, and model binding.
+
+To address this, the migration generator offers an optional **normalization step** that transforms composite primary
+keys into a **synthetic, single-column primary key**.
+
+### How It Works
+
+When the `--normalizer=primary-key` option is enabled:
+
+1. **Composite primary keys** are detected and removed.
+2. A synthetic `$table->id()` column is added as the new primary key.
+3. The original composite key is retained as a **named unique constraint**:
+   ```php
+   $table->unique(['user_id', 'role_id'], 'role_user_user_id_role_id_unique');
+   ```
+
+### Example
+
+**Legacy schema:**
+
+```sql
+CREATE TABLE role_user
+(
+    user_id INT,
+    role_id INT,
+    PRIMARY KEY (user_id, role_id)
+);
+```
+
+**Normalized Laravel migration:**
+
+```php
+Schema::create('role_user', function (Blueprint $table) {
+    $table->id(); // synthetic primary key
+    $table->unsignedBigInteger('user_id');
+    $table->unsignedBigInteger('role_id');
+
+    $table->unique(['user_id', 'role_id'], 'role_user_user_id_role_id_unique');
+    // Original primary key: PRIMARY KEY (user_id, role_id)
+});
+```
+
+### How to Enable
+
+Use the CLI option during migration generation:
+
+```bash
+php artisan migrate:regenerate --normalizer=primary-key
+```
+
+You can also enable it via the config file:
+
+```php
+// config/migration-generator.php
+'normalizer' => [
+    'enabled' => ['primary-key'],
+],
+```
+
+### Notes
+
+- This feature is **non-destructive**: the original uniqueness semantics are preserved.
+- Designed for compatibility with Laravel’s Eloquent, seeding, and testing tools.
+- Runs during the **pre-generation transformation phase**, before compilation.
+
 ## Dry-Run Mode (Planned)
 
 Coming soon: preview changes without writing files to disk.