build with uv rather than pip

The build command was `pip install .`, which is what the dora docs use because
`--uv` rewrites it. Spelling it `uv pip install .` means the dataflow never
installs through pip at all, whether or not `--uv` was passed. The cost is that
a node then needs a virtualenv to install into, so dataflows must be run with
`--uv`; AGENTS.md says so.

Note that the PR #3 branch still carries `pip install .`; landing this branch
on top of it is what corrects that.

dora-node.yml

@@ -13,10 +13,10 @@ keywords: [opencv, view, bbox, bounding-box, image, depth, intrinsics, camera-in
 
 runtime: python
 entrypoint: dora-image-view
-# `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.
-build: pip install .
+# Run the dataflow with --uv, which gives the node its own managed venv under
+# `.dora/python-envs/`, so what it imports at runtime is what was installed
+# here. Without --uv this needs a virtualenv to install into.
+build: uv pip install .
 dora: ">=1.0"
 
 inputs:
@@ -88,7 +88,7 @@ example: |
   - id: view
     git: ssh://git@gitea.liria.cl:5001/liria/dora-image-view.git
     tag: v0.1.0
-    build: pip install .
+    build: uv pip install .
     path: dora-image-view
     inputs:
       image: camera/image_bgr