Document volume mounts using the UI (#113)

* Document volume mounts using the UI

fixes: #111

Author: kantord

docs/toolhive/guides-ui/run-mcp-servers.md

@@ -50,7 +50,10 @@ On the configuration form, enter the following details:
 
    :::
 
-3. **Secrets** and **environment variables** expected by the server are
+3. To give the MCP server **access to the file system**, use the
+   [Volume mount](#volumes) feature. [Optional]
+
+4. **Secrets** and **environment variables** expected by the server are
    populated from the registry automatically. Required values are marked with an
    asterisk (\*).
    1. **Secrets**: Enter a value to create a new secret or select an existing
@@ -138,7 +141,10 @@ On the configuration form, enter:
    application-specific parameters. Refer to the MCP server's documentation for
    details.
 
-6. Any **secrets** or **environment variables** required by the MCP server.
+6. To give the MCP server **access to the file system**, use the
+   [Volume mount](#volumes) feature. [Optional]
+
+7. Any **secrets** or **environment variables** required by the MCP server.
    [Optional]\
    These might include API tokens, configuration options, or other sensitive
    data.
@@ -190,7 +196,10 @@ On the configuration form, enter:
    application-specific parameters. Refer to the MCP server's documentation for
    details.
 
-7. Any **secrets** or **environment variables** required by the MCP server.
+7. To give the MCP server **access to the file system**, use the
+   [Volume mount](#volumes) feature. [Optional]
+
+8. Any **secrets** or **environment variables** required by the MCP server.
    [Optional]\
    These might include API tokens, configuration options, or other sensitive
    data.
@@ -200,6 +209,24 @@ On the configuration form, enter:
 
 Click **Install server** to create and start the MCP server container.
 
+## Mount host files and folders (Volumes) {#volumes}
+
+Some MCP servers need access to files on your machine. You can mount host paths
+directly in the UI.
+
+1. In the server **Install / Configure** dialog, scroll to **Storage volumes**.
+2. Use the **first row** to create your mount:
+   - **Host path** — choose a file or folder on your computer.
+   - **Container path** — where it should appear inside the server (for example,
+     `/data`).
+   - By default, mounts are in read-write mode. If you want your volume mount to
+     be **Read-only**, select the "Read-only access" option from the drop-down.
+3. If you need additional mounts, click **Add a volume** and repeat.
+4. Click **Install server** to start the server with your volume(s).
+
+This applies to both registry-installed servers and custom servers (Docker image
+or source package).
+
 ## Manage MCP servers
 
 On the **MCP Servers** page, you can manage your installed MCP servers: