docs(quickstart): Add uv installation methods for developmental releases

why: Align with vcspull's documentation pattern and provide modern
installation options for users who prefer uv over pip.

what:
- Add uv installation examples with --prerelease allow for developmental releases
- Add uv git+https:// syntax for trunk installation
- Remove pipx/uvx/uv tool methods as libvcs is a library, not a CLI tool
- Simplify documentation to focus on package management tools relevant to libraries
- Test commands locally to verify syntax correctness

refs: Consistent with vcspull's approach to documenting installation methods

Author: tony

docs/quickstart.md

@@ -20,16 +20,22 @@ $ pip install --user --upgrade libvcs
 
 ### Developmental releases
 
-New versions of libvcs are published to PyPI as alpha, beta, or release candidates. In their
-versions you will see notification like `a1`, `b1`, and `rc1`, respectively. `1.10.0b4` would mean
-the 4th beta release of `1.10.0` before general availability.
+New versions of libvcs are published to PyPI as alpha, beta, or release candidates.
+In their versions you will see notification like `a1`, `b1`, and `rc1`, respectively.
+`1.10.0b4` would mean the 4th beta release of `1.10.0` before general availability.
 
 - [pip]\:
 
   ```console
   $ pip install --user --upgrade --pre libvcs
   ```
 
+- [uv]\:
+
+  ```console
+  $ uv add libvcs --prerelease allow
+  ```
+
 via trunk (can break easily):
 
 - [pip]\:
@@ -38,4 +44,11 @@ via trunk (can break easily):
   $ pip install --user -e git+https://github.com/vcs-python/libvcs.git#egg=libvcs
   ```
 
+- [uv]\:
+
+  ```console
+  $ uv add "git+https://github.com/vcs-python/libvcs.git"
+  ```
+
 [pip]: https://pip.pypa.io/en/stable/
+[uv]: https://docs.astral.sh/uv/