Add fern deep command to CLI reference

Added documentation for the new `fern deep` command that allows users to email Deep, one of our co-founders. The command supports optional --subject and --message flags, or can be run interactively without arguments.

Changes:
- Added `fern deep` entry to the main commands table
- Created detailed accordion documentation with usage examples
- Included options for subject and message parameters

Author: fern-support

fern/products/cli-api-reference/pages/commands.mdx

@@ -14,6 +14,7 @@ hideOnThisPage: true
 | [`fern logout`](#fern-logout) | Log out of the Fern CLI |
 | [`fern export`](#fern-export) | Export an OpenAPI spec for your API |
 | [`fern api update`](#fern-api-update) | Manually update your OpenAPI spec |
+| [`fern deep`](#fern-deep) | Email our co-founder, Deep |
 
 ## Documentation commands
 
@@ -587,4 +588,38 @@ hideOnThisPage: true
     ```
   </CodeBlock>
   </Accordion>
+
+  <Accordion title="fern deep">
+
+    Use `fern deep` to send an email directly to Deep, our co-founder. This command is useful when you need assistance, have feedback, or want to reach out to the Fern team.
+
+    <CodeBlock title="terminal">
+    ```bash
+    fern deep [--subject <subject>] [--message <message>]
+    ```
+    </CodeBlock>
+
+    When run without options, the command will open an interactive prompt to compose your message.
+
+    ### subject
+
+    Use `--subject` to specify the email subject line.
+
+    ```bash
+    fern deep --subject "Question about SDK generation"
+    ```
+
+    ### message
+
+    Use `--message` to include the email body directly in the command.
+
+    ```bash
+    fern deep --subject "Feature request" --message "Would love to see support for..."
+    ```
+
+    <Note>
+    You can also run `fern deep` without any options to compose your email interactively.
+    </Note>
+
+  </Accordion>
 </AccordionGroup>