fix: preserve literal f terminal input

spikes/gpui-shell/src/main.rs

@@ -1484,7 +1484,11 @@ fn terminal_key_from_parts(
         "delete" => TerminalKey::Delete,
         "pageup" => TerminalKey::PageUp,
         "pagedown" => TerminalKey::PageDown,
-        function if function.starts_with('f') => {
+        function
+            if function.strip_prefix('f').is_some_and(|suffix| {
+                !suffix.is_empty() && suffix.bytes().all(|byte| byte.is_ascii_digit())
+            }) =>
+        {
             let number = function.strip_prefix('f')?.parse::<u8>().ok()?;
             TerminalKey::Function(number)
         }
@@ -1557,6 +1561,12 @@ mod tests {
         let enter = terminal_key_from_parts("enter", None, KeyModifiers::default()).unwrap();
         assert_eq!(enter.key, TerminalKey::Enter);
 
+        let literal_f = terminal_key_from_parts("f", Some("f"), KeyModifiers::default()).unwrap();
+        assert_eq!(literal_f.key, TerminalKey::Text("f".into()));
+
+        let function = terminal_key_from_parts("f12", None, KeyModifiers::default()).unwrap();
+        assert_eq!(function.key, TerminalKey::Function(12));
+
         let composed = terminal_key_from_parts("é", Some("é"), KeyModifiers::default()).unwrap();
         assert_eq!(composed.key, TerminalKey::Text("é".into()));
     }