docs: fix uv installation command for zsh by quoting extras (#1523)

The original command:

    uv add langgraph-cli[inmem]

fails under zsh with:

    zsh: no matches found: langgraph-cli[inmem]

because zsh interprets `[...]` as a glob pattern. Adding quotes ensures
the extras syntax is passed correctly to uv:

    uv add "langgraph-cli[inmem]"

This fixes the installation instructions for macOS/zsh users.

Co-authored-by: Lauren Hirata Singh <[email protected]>

Author: wsypower

src/oss/langgraph/local-server.mdx

@@ -24,7 +24,7 @@ pip install -U "langgraph-cli[inmem]"
 
 ```bash uv
 # Python >= 3.11 is required.
-uv add langgraph-cli[inmem]
+uv add 'langgraph-cli[inmem]'
 ```
 </CodeGroup>
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