docs: add homebrew installation notes for mcp-publisher (#384)

- https://github.com/Homebrew/homebrew-core/pull/236635
- https://github.com/modelcontextprotocol/registry/issues/358
- https://formulae.brew.sh/formula/mcp-publisher

---------

Signed-off-by: Rui Chen <rui@chenrui.dev>
Co-authored-by: Adam Jones <adamj@anthropic.com>

docs/reference/cli/commands.md

@@ -6,15 +6,10 @@ See the [publishing guide](../../guides/publishing/publish-server.md) for a walk
 
 ## Installation
 
-<!-- TODO: update once #358 solved -->
+Install via Homebrew (macOS/Linux):
 
 ```bash
-# Build from source (from repository root)
-make publisher
-# Binary created at ./cmd/publisher/bin/mcp-publisher
-
-# Install globally (optional)
-cp ./cmd/publisher/bin/mcp-publisher /usr/local/bin/
+$ brew install mcp-publisher
 ```
 
 ## Global Options