ComfyUI docs: document ComfyUI-Manager custom node

ComfyUI-Manager (V3.41) is installed in the mounted custom_nodes dir and
self-installs its pip deps on start. Document the install command, the
bind-mount-shadows-image gotcha, and the /manager/version health check.

docs/Dankclaw/ComfyUI.md

@@ -41,6 +41,20 @@ Only the `video` group is added to the container. The `render` group (gid 990) i
 
 The ComfyUI code is baked into the image (not mounted). Rebuild the image to update the code.
 
+## Custom nodes
+
+Custom nodes go in `/home/dank/comfyui-data/custom_nodes` (mounted at `/opt/ComfyUI/custom_nodes`). ComfyUI loads every subdirectory there on start. Because this path is a bind mount, it shadows anything baked into the image — so custom nodes are installed host-side, not in the Containerfile.
+
+**ComfyUI-Manager** is installed here. Install it with a one-time clone, then restart the container:
+
+```bash
+git clone https://github.com/ltdrdata/ComfyUI-Manager \
+  /home/dank/comfyui-data/custom_nodes/ComfyUI-Manager
+systemctl --user restart comfyui
+```
+
+ComfyUI-Manager self-installs its own pip dependencies on start (GitPython, PyGithub, matrix-nio, transformers, and more). To confirm it loaded, query `GET /manager/version` (returns a version like `V3.41`). Its pip installs live in the container's writable layer, so they survive a restart and a reboot but not an image rebuild; after a rebuild, Manager re-installs them on the next start.
+
 ## Boot persistence
 
 The user systemd unit `~/.config/systemd/user/comfyui.service` runs `podman compose -f /home/dank/serverAppConfigs/dankclaw/compose.yaml up -d comfyui` at boot. It sets `WantedBy=default.target`, and user linger is on. The old CPU venv unit is preserved at `comfyui.service.venv.bak` as a fallback.