feat: show field coordinates in devmode (#1802)

Show the fields coordinates when the `devmode` search param is present.
It's meant to help API users understand where to position the fields.

apps/documentation/pages/developers/_meta.json

@@ -5,6 +5,7 @@
     "title": "Development & Deployment"
   },
   "local-development": "Local Development",
+  "developer-mode": "Developer Mode",
   "self-hosting": "Self Hosting",
   "contributing": "Contributing",
   "-- API & Integration Guides": {

apps/documentation/pages/developers/developer-mode/field-coordinates.mdx

@@ -0,0 +1,18 @@
+---
+title: Field Coordinates
+description: Learn how to get the coordinates of a field in a document.
+---
+
+## Field Coordinates
+
+Field coordinates represent the position of a field in a document. They are returned in the `pageX` and `pageY` properties of the field.
+
+To enable field coordinates, you can use the `devmode` query parameter.
+
+```bash
+https://app.documenso.com/documents/<document-id>/edit?devmode=true
+```
+
+You should then see the coordinates on top of each field.
+
+![Field Coordinates](/developer-mode/field-coordinates.webp)