feat(mcp) : add MCP resources, documentation, and .mcp.json config

- 3 MCP resources: schema, roles, stats
- docs/mcp/README.md with full user guide (config, tools catalogue, workflows)
- .mcp.json for Claude Code stdio transport
- Design spec and implementation plan

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/Mcp/Resource/SchemaResource.php

@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Mcp\Resource;
+
+use Mcp\Capability\Attribute\McpResource;
+use Mcp\Schema\Content\TextContent;
+
+#[McpResource(
+    uri: 'inventory://schema/entities',
+    name: 'Entity Schema',
+    description: 'Complete schema of all inventory entities with their fields, types, and relationships.',
+    mimeType: 'application/json'
+)]
+class SchemaResource
+{
+    public function __invoke(): array
+    {
+        $schema = [
+            'Machine' => [
+                'fields'        => ['id (string)', 'name (string, unique)', 'reference (string?)', 'prix (string?)', 'createdAt', 'updatedAt'],
+                'relationships' => ['site (Site, required)', 'constructeurs (Constructeur[])', 'componentLinks (MachineComponentLink[])', 'pieceLinks (MachinePieceLink[])', 'productLinks (MachineProductLink[])', 'customFields (CustomField[])', 'customFieldValues (CustomFieldValue[])'],
+            ],
+            'Composant' => [
+                'fields'        => ['id (string)', 'name (string, unique)', 'reference (string?)', 'description (text?)', 'prix (string?)', 'createdAt', 'updatedAt'],
+                'relationships' => ['typeComposant (ModelType?)', 'constructeurs (Constructeur[])', 'pieceSlots (ComposantPieceSlot[])', 'productSlots (ComposantProductSlot[])', 'subcomponentSlots (ComposantSubcomponentSlot[])', 'customFieldValues (CustomFieldValue[])'],
+            ],
+            'Piece' => [
+                'fields'        => ['id (string)', 'name (string)', 'reference (string?, unique)', 'description (text?)', 'prix (string?)', 'createdAt', 'updatedAt'],
+                'relationships' => ['typePiece (ModelType?)', 'product (Product?)', 'constructeurs (Constructeur[])', 'productSlots (PieceProductSlot[])', 'customFieldValues (CustomFieldValue[])'],
+            ],
+            'Product' => [
+                'fields'        => ['id (string)', 'name (string, unique)', 'reference (string?)', 'supplierPrice (string?)', 'createdAt', 'updatedAt'],
+                'relationships' => ['typeProduct (ModelType?)', 'constructeurs (Constructeur[])'],
+            ],
+            'Site' => [
+                'fields'        => ['id (string)', 'name (string)', 'contactName (string)', 'contactPhone (string)', 'contactAddress (string)', 'contactPostalCode (string)', 'contactCity (string)', 'color (string)', 'createdAt', 'updatedAt'],
+                'relationships' => ['machines (Machine[])'],
+            ],
+            'Constructeur' => [
+                'fields'        => ['id (string)', 'name (string, unique)', 'email (string?)', 'phone (string?)', 'createdAt', 'updatedAt'],
+                'relationships' => ['machines (Machine[])', 'composants (Composant[])', 'pieces (Piece[])', 'products (Product[])'],
+            ],
+            'ModelType' => [
+                'fields'        => ['id (string)', 'name (string)', 'category (machine|composant|piece|product)', 'code (string?)', 'createdAt', 'updatedAt'],
+                'relationships' => ['skeletonPieceRequirements[]', 'skeletonProductRequirements[]', 'skeletonSubcomponentRequirements[]'],
+            ],
+        ];
+
+        return [new TextContent(text: json_encode($schema, JSON_THROW_ON_ERROR | JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE))];
+    }
+}