add switch to docs

Author: skarim

README.md

@@ -418,6 +418,7 @@ gh stack up [n]      # Move up n branches (default 1)
 gh stack down [n]    # Move down n branches (default 1)
 gh stack top         # Jump to the top of the stack
 gh stack bottom      # Jump to the bottom of the stack
+gh stack switch      # Interactively pick a branch to switch to
 ```
 
 Navigation commands clamp to the bounds of the stack — moving up from the top or down from the bottom is a no-op with a message. If you're on the trunk branch, `up` moves to the first stack branch.
@@ -430,6 +431,7 @@ gh stack up 3        # move up three layers
 gh stack down
 gh stack top
 gh stack bottom
+gh stack switch      # shows an interactive picker
 ```
 
 ### `gh stack feedback`

docs/src/content/docs/reference/cli.md

@@ -410,6 +410,30 @@ gh stack bottom
 
 Checks out the branch closest to the trunk.
 
+### `gh stack switch`
+
+Interactively switch to another branch in the stack.
+
+```sh
+gh stack switch
+```
+
+Shows an interactive picker listing all branches in the current stack, ordered from top (furthest from trunk) to bottom (closest to trunk) with their position number. Select a branch to check it out.
+
+Requires an interactive terminal.
+
+**Examples:**
+
+```sh
+gh stack switch
+#    → Select a branch in the stack to switch to
+#      5. frontend
+#      4. api-endpoints
+#      3. auth-layer
+#      2. db-schema
+#      1. config-setup
+```
+
 ---
 
 ## Utilities