feat(cli): add --delete flag to /exit command for session deletion (#19332)

Co-authored-by: David Pierce <davidapierce@google.com>

docs/cli/tutorials/session-management.md

@@ -61,6 +61,19 @@ gemini --list-sessions
 gemini --delete-session 1
 ```
 
+### Scenario: Delete session on exit
+
+If you're doing a one-off task and don't want to leave any session history
+behind, use the `--delete` flag when exiting:
+
+```
+/exit --delete
+```
+
+This removes the current session's conversation history and tool output files
+before exiting. It's useful for privacy-sensitive tasks or quick one-off
+interactions.
+
 ## How to rewind time (Undo mistakes)
 
 Gemini CLI's **Rewind** feature is like `Ctrl+Z` for your workflow.

docs/reference/commands.md

@@ -323,6 +323,11 @@ Slash commands provide meta-level control over the CLI itself.
 ### `/quit` (or `/exit`)
 
 - **Description:** Exit Gemini CLI.
+- **Flags:**
+  - **`--delete`** _(optional)_: Exit and permanently delete the current
+    session's history and temporary files (chat recording, tool outputs). Useful
+    for privacy or one-off tasks where you don't want to leave any traces.
+  - **Usage:** `/quit --delete` or `/exit --delete`
 
 ### `/restore`