feat(05-02): install dnd-kit and create FieldPlacer component

- Install @dnd-kit/core@^6.3.1 and @dnd-kit/utilities@^3.2.2
- Create FieldPlacer.tsx with DndContext, draggable palette token, droppable PDF zone
- Implements Y-flip coordinate conversion (screenToPdfCoords / pdfToScreenCoords)
- Fetches existing fields from GET /api/documents/[id]/fields on mount
- Persists fields via PUT /api/documents/[id]/fields on every add/remove
- Renders placed fields as absolute-positioned blue-bordered overlays with remove button
- Default field size: 144x36 PDF points (2in x 0.5in at 72 DPI)

teressa-copeland-homes/package-lock.json

@@ -9,6 +9,8 @@
       "version": "0.1.0",
       "dependencies": {
         "@cantoo/pdf-lib": "^2.6.3",
+        "@dnd-kit/core": "^6.3.1",
+        "@dnd-kit/utilities": "^3.2.2",
         "@vercel/blob": "^2.3.1",
         "adm-zip": "^0.5.16",
         "bcryptjs": "^3.0.3",
@@ -597,6 +599,45 @@
         "tslib": ">=2"
       }
     },
+    "node_modules/@dnd-kit/accessibility": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/@dnd-kit/accessibility/-/accessibility-3.1.1.tgz",
+      "integrity": "sha512-2P+YgaXF+gRsIihwwY1gCsQSYnu9Zyj2py8kY5fFvUM1qm2WA2u639R6YNVfU4GWr+ZM5mqEsfHZZLoRONbemw==",
+      "license": "MIT",
+      "dependencies": {
+        "tslib": "^2.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=16.8.0"
+      }
+    },
+    "node_modules/@dnd-kit/core": {
+      "version": "6.3.1",
+      "resolved": "https://registry.npmjs.org/@dnd-kit/core/-/core-6.3.1.tgz",
+      "integrity": "sha512-xkGBRQQab4RLwgXxoqETICr6S5JlogafbhNsidmrkVv2YRs5MLwpjoF2qpiGjQt8S9AoxtIV603s0GIUpY5eYQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@dnd-kit/accessibility": "^3.1.1",
+        "@dnd-kit/utilities": "^3.2.2",
+        "tslib": "^2.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=16.8.0",
+        "react-dom": ">=16.8.0"
+      }
+    },
+    "node_modules/@dnd-kit/utilities": {
+      "version": "3.2.2",
+      "resolved": "https://registry.npmjs.org/@dnd-kit/utilities/-/utilities-3.2.2.tgz",
+      "integrity": "sha512-+MKAJEOfaBe5SmV6t34p80MMKhjvUz0vRrvVJbPT0WElzaOJ/1xs+D+KDv+tD/NE5ujfrChEcshd4fLn0wpiqg==",
+      "license": "MIT",
+      "dependencies": {
+        "tslib": "^2.0.0"
+      },
+      "peerDependencies": {
+        "react": ">=16.8.0"
+      }
+    },
     "node_modules/@drizzle-team/brocli": {
       "version": "0.10.2",
       "resolved": "https://registry.npmjs.org/@drizzle-team/brocli/-/brocli-0.10.2.tgz",