Generated images survive moves and renames

Agents tidy up folders after generating images (sort into subfolders, rename
revisions); the image records kept the old path, so /api/images/<id>/file
answered 404 and only the requesting device still showed them from its cache.

- Generated images get a copy in the image store (images.blob, kept by the
  blob GC); existing ones are copied once on start-up.
- Records follow: after bash commands with mv/rename (missing images of the
  owner from the last two weeks, found by name or by content hash), when moved
  with the file manager (file or folder), and on access (served from the copy,
  relocated in the background; without a copy found by file name).
- Chat gallery falls back to the preview the model saw when the file is gone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -3,6 +3,19 @@
 All notable changes to CodeCraft. Versions follow [Semantic Versioning](https://semver.org/);
 until 1.0, minor versions may contain breaking changes.
 
+## [Unreleased]
+
+### Fixed
+
+- **Generated images missing on other devices:** when an agent moved or renamed a generated
+  image afterwards (e.g. sorted it into subfolders), the gallery pointed to the old file – only
+  the device that had it in its browser cache still showed it. Now:
+  - generated images are also kept in the image store and shown from there when the file is gone
+    (existing images get their copy on the first start);
+  - their entries follow moves and renames: after an agent's `mv`/`rename`, when moved with the
+    file manager, and on the next view (found by file name, or by content when renamed);
+  - in the chat, an image that cannot be found falls back to the preview the model saw.
+
 ## [v202611-00014] – 2026-11-10
 
 ### Added