fix(admin-manual): replace placeholder text and fix redundant image paths

- Replace XXX/YYY GPU placeholders with realistic examples in AppAPI FAQ
- Fix grammar "does not supports" → "does not support"
- Simplify redundant ../configuration_server/ figure paths in theming.rst

AI-Assisted-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Anna Larch <anna@nextcloud.com>

Author: miaulalala

admin_manual/configuration_server/theming.rst

@@ -11,7 +11,7 @@ Customize the appearance of Nextcloud
 
 You can change the following aspects of your instance's appearance:
 
-.. figure:: ../configuration_server/images/theming1.png
+.. figure:: images/theming1.png
 
 * **Name** (e.g., ACME Inc. Cloud).
 * **Web link** (e.g., https://acme.inc/).
@@ -21,7 +21,7 @@ You can change the following aspects of your instance's appearance:
 * **Logo**: Appears in the header and on the login page (default size: 62x34 px).
 * **Background and login image**: Sets the page background.
 
-.. figure:: ../configuration_server/images/theming2.png
+.. figure:: images/theming2.png
 
 * **Additional legal links**: Legal notice and privacy policy.
 * **Custom header logo and favicon**: Optionally override the auto-generated favicon based on your logo.

admin_manual/exapps_management/AppAPIAndExternalApps.rst

@@ -100,9 +100,9 @@ If successful, the ExApp will be displayed under the "Your apps" list.
 FAQ
 ---
 
-* I have two graphics cards XXX with 6/8/Y GB of ram each. How can I run something which does not fit into one graphics card?
+* I have two graphics cards (e.g. NVIDIA RTX 3060) with 8 GB of VRAM each. How can I run something which does not fit into one graphics card?
     * Distributing models across multiple GPUs is currently not supported. You will need a GPU that fits all of the model you are trying to use.
-* I have YYY graphics card that does not supports CUDA - can I use it and how?
+* I have a graphics card that does not support CUDA - can I use it and how?
     * No, our AI apps require GPUs with CUDA support to function at this time.
 * What is the minimum VRAM size requirement for the GPU if I want to install multiple apps?
     * When running multiple ExApps on the same GPU, the GPU must hold the largest model amongst the apps you install.