Add single-command installation: install.sh, Makefile, frontend build hook

- hatch_build.py: custom hatchling build hook that compiles the React
  frontend (npm ci + build) when frontend/dist is missing or stale, so
  'uv tool install git+https://gitea.zephyre.one/Pakobbix/nvcurve.git'
  works as a single command
- install.sh: curl|bash installer (checks prerequisites, auto-installs uv,
  clones and installs)
- Makefile: dev targets (frontend, install, dev, test, clean)
- README/docs: document the one-liner, clone, and direct-git installs

pyproject.toml

@@ -19,9 +19,20 @@ dependencies = [
 [project.scripts]
 nvcurve = "nvcurve.cli:main"
 
+[dependency-groups]
+dev = [
+    "hatchling",  # enables local `hatch build` and resolves hatch_build.py imports
+]
+
+[tool.hatch.build.hooks.custom]
+
 [tool.hatch.build.targets.wheel]
 packages = ["nvcurve"]
 
+# The custom build hook (hatch_build.py) compiles the React frontend when
+# frontend/dist is missing or stale, so `uv tool install git+<repo-url>` works
+# as a single command. It runs for both wheel and sdist builds.
+
 [tool.hatch.build.targets.wheel.force-include]
 "frontend/dist" = "nvcurve/frontend/dist"