docs: Add installation page

why: Separating installation mechanics from client configuration and
quickstart follows the pattern used by Playwright and GitHub MCP servers.
what:
- Create docs/installation.md with requirements, uvx, pip, dev install
- Include upgrade and run instructions
- Link to clients page for MCP client wiring

Author: tony

docs/installation.md

@@ -0,0 +1,67 @@
+(installation)=
+
+# Installation
+
+## Requirements
+
+- Python 3.10+
+- tmux >= 3.2a
+- [uv](https://docs.astral.sh/uv/) (recommended) or pip
+
+## Recommended: uvx
+
+`uvx` handles install, deps, and execution in one step — no persistent install needed:
+
+```console
+$ uvx libtmux-mcp
+```
+
+To wire it into your MCP client, see {ref}`clients`.
+
+## pip / uv pip
+
+```console
+$ uv pip install libtmux-mcp
+```
+
+```console
+$ pip install libtmux-mcp
+```
+
+## Development install
+
+Clone and install in editable mode:
+
+```console
+$ git clone https://github.com/tmux-python/libtmux-mcp.git
+```
+
+```console
+$ cd libtmux-mcp
+```
+
+```console
+$ uv pip install -e "."
+```
+
+Code changes take effect immediately — no reinstall needed.
+
+## Running the server
+
+```console
+$ libtmux-mcp
+```
+
+Or via Python module:
+
+```console
+$ python -m libtmux_mcp
+```
+
+## Upgrading
+
+```console
+$ uv pip install --upgrade libtmux-mcp
+```
+
+With `uvx`, you always get the latest version automatically.