feat: add "Choose from Server" attachment picker to claim/preauth forms and chatbot

Native file inputs can't be pointed at a default server folder for security
reasons, so instead the Browse buttons on the Claim/PreAuth/Select Procedures
forms and the AI chatbot's attach button now also offer picking from
previously saved Cloud Storage attachments (e.g. Copy Agent screenshots) via
a new server-side picker modal, scoped per-patient on the claim forms and
unscoped (recent across all patients) in the chatbot.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/Backend/src/storage/cloudStorage-storage.ts

@@ -161,6 +161,7 @@ export interface IStorage {
     patientId: number,
     category: string
   ): Promise<CloudFile[]>;
+  listRecentAttachmentFiles(limit?: number): Promise<CloudFile[]>;
 }
 
 /* ------------------------------- Implementation ------------------------------- */
@@ -663,6 +664,25 @@ export const cloudStorageStorage: IStorage = {
     return files.map(serializeFile) as unknown as CloudFile[];
   },
 
+  async listRecentAttachmentFiles(limit: number = 20) {
+    const files = await db.cloudFile.findMany({
+      where: { folder: { name: "Attachments" }, isComplete: true },
+      orderBy: { createdAt: "desc" },
+      take: limit,
+      select: {
+        id: true,
+        name: true,
+        mimeType: true,
+        fileSize: true,
+        folderId: true,
+        isComplete: true,
+        createdAt: true,
+        updatedAt: true,
+      },
+    });
+    return files.map(serializeFile) as unknown as CloudFile[];
+  },
+
   // --- STREAM ---
   async streamFileTo(resStream: NodeJS.WritableStream, fileId: number) {
     const file = await db.cloudFile.findUnique({