fix(python): clean up setuptools usage and drop redundant/unnecessary lock files (github#449)

* Rely on `pyproject.toml`
Use of `setup.py` is redundant.

This leads to more accurate metadata:
```diff
17c17
< Requires-Python: >=3.8
---
> Requires-Python: >=3.9
29d28
< Dynamic: requires-python
```

* Drop unnecessary/redundant lock files

* Don't require a lock file

Author: brettcannon

.github/workflows/python-sdk-tests.yml

@@ -59,7 +59,7 @@ jobs:
           enable-cache: true
 
       - name: Install Python dev dependencies
-        run: uv sync --locked --all-extras --dev
+        run: uv sync --all-extras --dev
 
       - name: Install Node.js dependencies (for CLI in tests)
         working-directory: ./nodejs

python/.gitignore

@@ -163,6 +163,9 @@ cython_debug/
 .ruff_cache/
 .ty_cache/
 
+# uv
+uv.lock
+
 # Build script caches
 .cli-cache/
 .build-temp/

python/pyproject.toml

@@ -32,10 +32,6 @@ dependencies = [
 Homepage = "https://github.com/github/copilot-sdk"
 Repository = "https://github.com/github/copilot-sdk"
 
-[tool.setuptools.packages.find]
-where = ["."]
-include = ["copilot*"]
-
 [project.optional-dependencies]
 dev = [
     "ruff>=0.1.0",
@@ -46,6 +42,9 @@ dev = [
     "httpx>=0.24.0",
 ]
 
+[tool.setuptools]
+packages = ["copilot"]
+
 [tool.ruff]
 line-length = 100
 target-version = "py39"