refactor: rename the node from opencv-plot to dora-plot

The repository is dora-plot, but the package, the entrypoint, the manifest
name and the window title were all opencv-plot. Consumers wire the node by
`path:`, so the split name was visible in every dataflow.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018WLVZCFFcCH1EpTXGfS9aD

dora-node.yml

@@ -5,14 +5,14 @@
 # dataflow against it without running the node, so CI needs neither OpenCV nor
 # a display.
 apiVersion: 1
-name: opencv-plot
+name: dora-plot
 namespace: liria
 description: Overlays bounding boxes, labels, and text on an image input and displays it in an OpenCV window
 categories: [visualization, debug]
 keywords: [opencv, plot, bbox, bounding-box, image, visualization, object-detection]
 
 runtime: python
-entrypoint: opencv-plot
+entrypoint: dora-plot
 # `dora build --uv` / `dora run --uv` rewrites this to `uv pip install .` and
 # gives the node its own managed venv under `.dora/python-envs/`, so the
 # dependencies it sees at runtime are the ones installed here.
@@ -57,7 +57,7 @@ example: |
     git: ssh://git@gitea.liria.cl:5001/liria/dora-plot.git
     tag: v0.1.0
     build: pip install .
-    path: opencv-plot
+    path: dora-plot
     inputs:
       image: camera/image
       bbox: detector/bbox