Improve attachment memory safety, downloads, and high-memory alert UX.

Stream large receives to disk with chunk acks to cap renderer RAM, evict
off-screen display blobs, and route exports through a disk-aware download
service. Fix the high-memory dialog (backdrop dismiss, copy, log actions),
allow diagnostics paths in the path jail, and restore persisted image
hydration after reload.

Co-authored-by: Cursor <cursoragent@cursor.com>

toju-app/src/app/domains/attachment/application/services/attachment-persistence.service.ts

@@ -11,6 +11,7 @@ import {
   decodeBase64ToUint8Array,
   yieldToAttachmentHydrationLoop
 } from '../../domain/logic/attachment-blob.rules';
+import { canRevokeAttachmentDisplayBlob } from '../../domain/logic/attachment-blob-eviction.rules';
 import { isBlobObjectUrl, needsBlobObjectUrlForInlineDisplay } from '../../domain/logic/attachment-display-url.rules';
 import { mergeAttachmentLocalPaths } from '../../domain/logic/attachment-persistence.rules';
 import { isAttachmentMedia } from '../../domain/logic/attachment.logic';
@@ -119,7 +120,7 @@ export class AttachmentPersistenceService {
   }
 
   async tryRestoreAttachmentFromLocal(attachment: Attachment): Promise<boolean> {
-    const restored = await this.ensurePersistedUploadHost(attachment);
+    const restored = await this.ensurePersistedUploadHost(attachment, { hydrateMediaForDisplay: true });
 
     if (restored) {
       attachment.requestError = undefined;
@@ -128,11 +129,30 @@ export class AttachmentPersistenceService {
     return restored;
   }
 
-  async ensurePersistedUploadHost(attachment: Attachment): Promise<boolean> {
+  async tryRestoreAttachmentHostOnly(attachment: Attachment): Promise<boolean> {
+    return this.ensurePersistedUploadHost(attachment, { hydrateMediaForDisplay: false });
+  }
+
+  revokeAttachmentDisplayBlob(attachment: Attachment): boolean {
+    if (!canRevokeAttachmentDisplayBlob(attachment)) {
+      return false;
+    }
+
+    this.revokeAttachmentObjectUrl(attachment);
+    attachment.objectUrl = undefined;
+
+    return true;
+  }
+
+  async ensurePersistedUploadHost(
+    attachment: Attachment,
+    options: { hydrateMediaForDisplay?: boolean } = {}
+  ): Promise<boolean> {
+    const hydrateMediaForDisplay = options.hydrateMediaForDisplay !== false;
     const existingPath = await this.attachmentStorage.resolveExistingPath(attachment);
 
     if (existingPath) {
-      return this.hydrateAttachmentFromStoredPath(attachment, existingPath);
+      return this.hydrateAttachmentFromStoredPath(attachment, existingPath, hydrateMediaForDisplay);
     }
 
     if (!attachment.filePath?.trim() || !this.attachmentStorage.canCopyFiles()) {
@@ -147,13 +167,22 @@ export class AttachmentPersistenceService {
       return false;
     }
 
-    return this.hydrateAttachmentFromStoredPath(attachment, savedPath);
+    return this.hydrateAttachmentFromStoredPath(attachment, savedPath, hydrateMediaForDisplay);
   }
 
-  private async hydrateAttachmentFromStoredPath(attachment: Attachment, diskPath: string): Promise<boolean> {
+  private async hydrateAttachmentFromStoredPath(
+    attachment: Attachment,
+    diskPath: string,
+    hydrateMediaForDisplay = true
+  ): Promise<boolean> {
     attachment.savedPath = diskPath;
 
     if (isAttachmentMedia(attachment)) {
+      if (!hydrateMediaForDisplay) {
+        void this.persistAttachmentMeta(attachment);
+        return true;
+      }
+
       return this.ensureInlineDisplayObjectUrl(attachment);
     }
 
@@ -192,6 +221,7 @@ export class AttachmentPersistenceService {
         this.revokeAttachmentObjectUrl(attachment);
         attachment.objectUrl = nativeUrl;
         attachment.available = true;
+        this.runtimeStore.touch();
         return true;
       }
     }
@@ -366,6 +396,8 @@ export class AttachmentPersistenceService {
       `${attachment.messageId}:${attachment.id}`,
       new File([blob], attachment.filename, { type: attachment.mime })
     );
+
+    this.runtimeStore.touch();
   }
 
   private revokeAttachmentObjectUrl(attachment: Attachment): void {