feat: add CameraErrorCode enum for type-safe error handling

[andredestro]

Summary

Adds a CameraErrorCode TypeScript enum that exposes all error codes returned by the Camera plugin, enabling type-safe error handling without relying on raw strings.

Reference #43

What changed

• Added CameraErrorCode enum to src/definitions.ts with 24 error codes grouped by category (Permissions, Take Photo, Edit Photo, Choose from Gallery, Record Video, Play Video, General)
• Each value follows the existing OS-PLUG-CAMR-XXXX format already returned in rejected promise payloads
• Platform-specific codes are annotated with @platform ios or @platform android in JSDoc
• Automatically exported via the existing export * from './definitions' barrel in src/index.ts

Usage

Before:

camera.getPhoto(...).catch((err) => {
  if (err.code === 'OS-PLUG-CAMR-0003') {
    // handle camera permission denied
  }
});

After:

import { CameraErrorCode } from '@capacitor/camera';

camera.getPhoto(...).catch((err) => {
  if (err.code === CameraErrorCode.CameraPermissionDenied) {
    // handle camera permission denied
  }
});