uv dev environment, README writing pass, publish hygiene

- pyproject.toml + uv.lock: uv-managed dev environment (uv sync /
  uv run pytest). requirements.txt stays: KiCad builds the plugin's
  runtime venv from it and the PCM zip packages it.
- README: em-dash and run-on cleanup (34 -> 22, the rest deliberate),
  split the 120-word THT solder-joint sentence, fix the documented
  ADAPTIVE_MAX_CELL_UM value (2 mm -> 1 mm, config has 1000 um), fix
  the *Packaging / publishing* cross-reference, dev sections now use
  uv sync / uv run.
- LLM disclaimer: "most commits" carry the trailer (32 of 39), figures
  claim now excepts the hand-drawn hole cross-section, reference the
  UT3513+ measured-vs-computed validation.
- .gitignore: local AI-tooling artifacts; deploy scripts exclude
  pyproject.toml/uv.lock; error-figure title punctuation aligned with
  the other window titles.

tools/deploy.py

@@ -18,7 +18,7 @@ from pathlib import Path
 ROOT = Path(__file__).resolve().parent.parent
 COPY_EXCLUDE = {".venv", ".git", "tests", "tools", "dist", "resources",
                 "__pycache__", ".pytest_cache", "conftest.py", "deploy.ps1",
-                ".gitignore", "metadata.json"}
+                ".gitignore", "metadata.json", "pyproject.toml", "uv.lock"}
 
 
 def plugins_dir(kicad_version: str) -> Path: