manyfold: update to 0.133.1, remove image field, add migration docs

- Bump version to 0.133.1 (latest upstream manyfold-solo release)
- Remove image: field from config.yaml so HA builds via Dockerfile
- Pin Dockerfile and build.yaml to 0.133.1 instead of :latest
- Add Secret Key Base section to README covering all install scenarios
- Add Migration section to README with steps to preserve data when
  switching addon slug or reinstalling

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

manyfold/Dockerfile

@@ -1,4 +1,4 @@
-ARG BUILD_FROM=ghcr.io/manyfold3d/manyfold-solo:latest
+ARG BUILD_FROM=ghcr.io/manyfold3d/manyfold-solo:0.133.1
 FROM ${BUILD_FROM}
 
 # hadolint ignore=DL3041

manyfold/README.md

@@ -52,7 +52,7 @@ Local development alternative on the HA host:
 
 ## Options
 
-- `secret_key_base`: App secret. Auto-generated and persisted at `/config/secret_key_base` when empty.
+- `secret_key_base`: App secret used by Rails to sign/encrypt sessions and tokens. See [Secret Key Base](#secret-key-base) below.
 - `puid` / `pgid`: Ownership applied to writable mapped directories (`/config` paths).
 - `multiuser`: Toggle Manyfold multiuser mode.
 - `library_path`: Scanned/indexed path.
@@ -126,6 +126,40 @@ After changing values:
 - `thumbnails_path` must resolve under `/config` to guarantee persistence.
 - Startup fails if `library_path` is not readable.
 
+## Secret Key Base
+
+`secret_key_base` is a required Rails secret used to sign and encrypt user sessions and tokens. Changing it will invalidate all active sessions and log everyone out.
+
+**How it works:**
+
+| Scenario | Behaviour |
+|----------|-----------|
+| **New install**, option left blank | A random secret is auto-generated and saved to `/config/secret_key_base` |
+| **Addon update**, option still blank | The previously saved `/config/secret_key_base` is reused — no data loss |
+| **Option manually set** | The value from the addon options is used and saved to `/config/secret_key_base` |
+| **Option was set, then cleared on update** | A new secret is generated — **sessions will be invalidated** |
+
+**Recommendation:** Leave `secret_key_base` blank on first install and never change it afterwards. The auto-generated value persists across updates in `/config/secret_key_base`, which is included in Home Assistant backups.
+
+## Migrating from a previous installation
+
+If you are reinstalling this addon or moving from another Manyfold addon (e.g. a different slug/repository), your data is stored in the previous addon's config directory on the HA host. To migrate without losing data:
+
+1. SSH into your Home Assistant host.
+2. Copy the database and secret to the new addon config directory:
+
+```bash
+cp /addon_configs/<old_slug>/manyfold.sqlite3 /addon_configs/<new_slug>/manyfold.sqlite3
+cp /addon_configs/<old_slug>/secret_key_base /addon_configs/<new_slug>/secret_key_base
+chown 1000:1000 /addon_configs/<new_slug>/manyfold.sqlite3 /addon_configs/<new_slug>/secret_key_base
+chown 1000:1000 /addon_configs/<new_slug>/
+chmod 600 /addon_configs/<new_slug>/secret_key_base
+```
+
+Replace `<old_slug>` and `<new_slug>` with the actual directory names (e.g. `db21ed7f_manyfold` and `088d77ac_manyfold_solo`). List them with `ls /addon_configs/`.
+
+3. Start the new addon — it will pick up the existing database and secret automatically.
+
 ## Notes
 
 - This baseline avoids Home Assistant ingress and keeps direct port access.

manyfold/build.yaml

@@ -1,4 +1,4 @@
 ---
 build_from:
-  aarch64: ghcr.io/manyfold3d/manyfold-solo:latest
-  amd64: ghcr.io/manyfold3d/manyfold-solo:latest
+  aarch64: ghcr.io/manyfold3d/manyfold-solo:0.133.1
+  amd64: ghcr.io/manyfold3d/manyfold-solo:0.133.1

manyfold/config.yaml

@@ -1,9 +1,8 @@
 name: "Manyfold"
 slug: manyfold
 description: "Manyfold 3D model manager as a Home Assistant add-on, using the upstream image with configurable library/index paths."
-version: "1.0.3"
+version: "0.133.1"
 url: "https://github.com/alexbelgium/hassio-addons/tree/master/manyfold"
-image: ghcr.io/alexbelgium/manyfold-{arch}
 arch:
   - amd64
   - aarch64