Workflow links: single-preview rows span both columns

Follow-up to #17. Templates that have a single preview now span both preview columns instead of leaving the second cell empty, so the table no longer shows blank cells.

Adds a **Workflows** section to the model card so the templates that work with these files can be opened or downloaded straight from the repo page.

- 1 templates from [Comfy-Org/workflow_templates](https://github.com/Comfy-Org/workflow_templates), all first-party (no community `templates_*` submissions) and all runnable with stock ComfyUI nodes.
- Attribution follows the template library's own `models` metadata: a template is listed here only when the model it belongs to is the one hosted in this repo. Templates that merely borrow this repo's files are left out.
- Each row shows the template's preview at a uniform 200 px, laid out side by side under a fixed two-column grid so single- and dual-preview templates line up. Dual-preview templates show their before/after pair, labelled, in the order before → after.
- Ordered by template usage, most used first.

Replaces the previous short workflow list with the full set.

Nothing else in the README is changed.

---

*This change was prepared with AI assistance (ComfyUI-Wiki) and reviewed before merge.*

README.md

@@ -37,6 +37,6 @@ Place the files in the following folders:
 <tr><th align="center" valign="middle" style="text-align:center;vertical-align:middle">Workflow</th><th colspan="2" align="center" valign="middle" style="text-align:center;vertical-align:middle">Thumb</th></tr>
 </thead>
 <tbody>
-<tr><td align="center" valign="middle" style="text-align:center;vertical-align:middle"><a href="https://github.com/Comfy-Org/workflow_templates/blob/main/templates/audio_minimax_music_3.json">MiniMax Music 3: Text to Music</a></td><td align="center" valign="middle" style="text-align:center;vertical-align:middle"><a href="https://github.com/Comfy-Org/workflow_templates/blob/main/templates/audio_minimax_music_3.json"><img src="https://raw.githubusercontent.com/Comfy-Org/workflow_templates/main/templates/audio_minimax_music_3-1.webp" width="200" height="200" alt="MiniMax Music 3: Text to Music"></a></td><td align="center" valign="middle" style="text-align:center;vertical-align:middle"></td></tr>
+<tr><td align="center" valign="middle" style="text-align:center;vertical-align:middle"><a href="https://github.com/Comfy-Org/workflow_templates/blob/main/templates/audio_minimax_music_3.json">MiniMax Music 3: Text to Music</a></td><td colspan="2" align="center" valign="middle" style="text-align:center;vertical-align:middle"><a href="https://github.com/Comfy-Org/workflow_templates/blob/main/templates/audio_minimax_music_3.json"><img src="https://raw.githubusercontent.com/Comfy-Org/workflow_templates/main/templates/audio_minimax_music_3-1.webp" width="200" height="200" alt="MiniMax Music 3: Text to Music"></a></td></tr>
 </tbody>
 </table>