feat: feedback with photo support + web dashboard feedback button

iOS:
- Photo picker in feedback sheet (screenshot/photo attachment)
- Image sent as base64, uploaded to Gitea issue as attachment

Web:
- Feedback button in sidebar rail
- Modal with text area + send
- Auto-labels same as iOS

Gateway:
- Multipart image upload to Gitea issue assets API

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

ios/Platform/Platform/Features/Feedback/FeedbackView.swift

@@ -1,4 +1,5 @@
 import SwiftUI
+import PhotosUI
 
 struct FeedbackButton: View {
     @State private var showSheet = false
@@ -15,7 +16,7 @@ struct FeedbackButton: View {
         }
         .sheet(isPresented: $showSheet) {
             FeedbackSheet()
-                .presentationDetents([.medium])
+                .presentationDetents([.large, .medium])
         }
     }
 }
@@ -26,6 +27,9 @@ struct FeedbackSheet: View {
     @State private var isSending = false
     @State private var sent = false
     @State private var error: String?
+    @State private var selectedPhoto: PhotosPickerItem?
+    @State private var photoData: Data?
+    @State private var photoPreview: UIImage?
 
     var body: some View {
         VStack(spacing: 16) {
@@ -64,6 +68,43 @@ struct FeedbackSheet: View {
                             .stroke(Color.textTertiary.opacity(0.2), lineWidth: 1)
                     )
 
+                // Photo attachment
+                HStack {
+                    PhotosPicker(selection: $selectedPhoto, matching: .screenshots) {
+                        HStack(spacing: 6) {
+                            Image(systemName: "camera.fill")
+                                .font(.caption)
+                            Text(photoPreview != nil ? "Change photo" : "Add screenshot")
+                                .font(.caption.weight(.medium))
+                        }
+                        .foregroundStyle(Color.accentWarm)
+                        .padding(.horizontal, 12)
+                        .padding(.vertical, 8)
+                        .background(Color.accentWarm.opacity(0.1))
+                        .clipShape(Capsule())
+                    }
+
+                    if let preview = photoPreview {
+                        Image(uiImage: preview)
+                            .resizable()
+                            .scaledToFill()
+                            .frame(width: 40, height: 40)
+                            .clipShape(RoundedRectangle(cornerRadius: 8))
+
+                        Button {
+                            photoData = nil
+                            photoPreview = nil
+                            selectedPhoto = nil
+                        } label: {
+                            Image(systemName: "xmark.circle.fill")
+                                .font(.caption)
+                                .foregroundStyle(Color.textTertiary)
+                        }
+                    }
+
+                    Spacer()
+                }
+
                 if let error {
                     Text(error)
                         .font(.caption)
@@ -90,6 +131,15 @@ struct FeedbackSheet: View {
         }
         .padding()
         .background(Color.surfaceCard)
+        .onChange(of: selectedPhoto) {
+            Task {
+                if let item = selectedPhoto,
+                   let data = try? await item.loadTransferable(type: Data.self) {
+                    photoData = data
+                    photoPreview = UIImage(data: data)
+                }
+            }
+        }
     }
 
     private func sendFeedback() {
@@ -98,7 +148,10 @@ struct FeedbackSheet: View {
 
         Task {
             do {
-                let body: [String: String] = ["text": text.trimmingCharacters(in: .whitespaces), "source": "ios"]
+                var body: [String: Any] = ["text": text.trimmingCharacters(in: .whitespaces), "source": "ios"]
+                if let imgData = photoData {
+                    body["image"] = imgData.base64EncodedString()
+                }
                 let jsonData = try JSONSerialization.data(withJSONObject: body)
                 let data = try await APIClient.shared.rawPost(path: "/api/feedback", data: jsonData)