Specify --target-port on docs and match port on quickstart guide (#47)

* Specify --target-port on docs and match port on quickstart guide

AFAIK we have 2 ports: the proxy port in which ToolHive runs and
a hardcoded port that may be used by an MCP server. For the second
one, the current flag should be `--target-port` instead of `--port`.
Changed the only reference I could find in docs.

Also, there was a small typo in the quickstart guide in the ports.
The text was talking about port `49226` but the port shown in the
example was port `15266`.

* Reverted port on example

* Apply suggestions from code review

Co-authored-by: Dan Barr <[email protected]>

---------

Co-authored-by: Dan Barr <[email protected]>

Author: aponcedeleonch

docs/toolhive/guides-cli/run-mcp-servers.mdx

@@ -143,7 +143,8 @@ Check the MCP server's documentation for the required arguments.
 ### Run a server on a specific port
 
 ToolHive creates a reverse proxy on a random port that forwards requests to the
-container. To specify the port for an MCP server:
+container. This is the port that client applications connect to. To set a
+specific proxy port instead, use the `--port` flag:
 
 ```bash
 thv run --port <port-number> <server-name>

docs/toolhive/tutorials/quickstart.mdx

@@ -217,7 +217,7 @@ NAME    PACKAGE            STATUS    URL                                PORT
 fetch   mcp/fetch:latest   running   http://127.0.0.1:15266/sse#fetch   15266   mcp         2025-06-30 09:12:53 -0400 EDT
 ```
 
-This confirms that the fetch server is running and available on port 49226.
+This confirms that the fetch server is running and available on port 15266.
 
 :::info What's happening?