Add image attachments to feedback form (JPEG/PNG)

- File input in feedback modal (max 3 images, 5 MB each)
- Frontend validation for file count and size
- Backend: multipart/form-data with UploadFile, MIME attachments
- Images attached to feedback email as base64-encoded attachments
- Only JPEG and PNG allowed (validated server-side)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/static/js/api.js

@@ -197,6 +197,23 @@ const API = {
         return this._request('POST', '/feedback', data);
     },
 
+    async sendFeedbackForm(formData) {
+        const token = localStorage.getItem('osint_token');
+        const controller = new AbortController();
+        const timeout = setTimeout(() => controller.abort(), 60000);
+        const resp = await fetch(this.baseUrl + '/feedback', {
+            method: 'POST',
+            headers: { 'Authorization': token ? 'Bearer ' + token : '' },
+            body: formData,
+            signal: controller.signal,
+        });
+        clearTimeout(timeout);
+        if (!resp.ok) {
+            const err = await resp.json().catch(() => ({}));
+            throw new Error(err.detail || 'Fehler ' + resp.status);
+        }
+    },
+
     // Export
     exportIncident(id, format, scope) {
         const token = localStorage.getItem('osint_token');