pmacs-gpu: forward chorded deletion keys (C-BS word delete)

Backspace/Delete with modifiers were withheld by the chord filter,
so C-BS / C-DEL / M-BS — word-level deletes in the default keymap —
silently did nothing in the GPU while C-<left> word motion worked.
Deletion keys now forward with their modifiers exactly like motion
keys; an unbound chord is a harmless no-op at the daemon keymap, and
chorded deletes never apply optimistically (optimistic_delete_range
requires empty modifiers), so they always round-trip into their
bound commands. Acceptance test drives C-BS / C-DEL through the real
dispatch path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pmacs-gpu/src/main.rs

@@ -2649,26 +2649,31 @@ fn is_motion_key(key: ProtocolKey) -> bool {
 }
 
 /// Whether to forward a translated key to the daemon (session B2).
-/// Motion keys go through with any modifiers. Plain text-editing keys
-/// (`Char` / `Backspace` / `Enter` / `Delete` / `Tab`) go through only
-/// *without* a Ctrl/Alt/Meta chord modifier: a bare key edits text,
-/// but a chord drives commands and minibuffer flows the GUI can't
-/// render or interact with yet (deferred to a later session). Shift is
-/// not a chord modifier — `Shift`+a already arrives as `Char('A')`.
+/// Motion keys go through with any modifiers (C-<left> is word
+/// motion). Deletion keys do too: C-BS / C-DEL / M-BS are word-level
+/// deletes in the default keymap — the same editing-command family as
+/// chorded motion, and an unbound chord is a harmless no-op at the
+/// daemon keymap. (Chorded deletes never apply optimistically:
+/// `optimistic_delete_range` requires empty modifiers, so they always
+/// round-trip into their bound commands.) The remaining text keys
+/// (`Char` / `Enter` / `Tab`) go through only *without* a
+/// Ctrl/Alt/Meta chord modifier: a bare key edits text, but those
+/// chords drive commands and minibuffer flows the GUI can't render or
+/// interact with yet (deferred to a later session). Shift is not a
+/// chord modifier — `Shift`+a already arrives as `Char('A')`.
 fn should_forward_key(key: ProtocolKey, mods: Modifiers) -> bool {
     if is_motion_key(key) {
         return true;
     }
+    if matches!(key, ProtocolKey::Backspace | ProtocolKey::Delete) {
+        return true;
+    }
     if !is_plain_text_modifiers(mods) {
         return false;
     }
     matches!(
         key,
-        ProtocolKey::Char(_)
-            | ProtocolKey::Backspace
-            | ProtocolKey::Enter
-            | ProtocolKey::Delete
-            | ProtocolKey::Tab
+        ProtocolKey::Char(_) | ProtocolKey::Enter | ProtocolKey::Tab
     )
 }
 
@@ -3600,6 +3605,13 @@ mod tests {
         assert!(should_forward_key(ProtocolKey::Left, ctrl));
         assert!(should_forward_key(ProtocolKey::Down, shift));
         assert!(should_forward_key(ProtocolKey::PageUp, none));
+
+        // Deletion keys forward regardless of modifiers too — C-BS /
+        // C-DEL / M-BS are word-level deletes in the default keymap,
+        // the same editing-command family as chorded motion.
+        assert!(should_forward_key(ProtocolKey::Backspace, ctrl));
+        assert!(should_forward_key(ProtocolKey::Delete, ctrl));
+        assert!(should_forward_key(ProtocolKey::Backspace, Modifiers::ALT));
     }
 
     #[test]

tests/cua_region_acceptance.rs

@@ -74,6 +74,32 @@ fn backspace_deletes_the_shift_selected_region() {
     assert_eq!(cursor, 1);
 }
 
+/// C-Backspace deletes the previous word (and C-Delete the next),
+/// mirroring C-arrow word motion. The pmacs-gpu frontend forwards
+/// chorded deletion keys to this same dispatch path.
+#[test]
+fn ctrl_backspace_deletes_the_previous_word() {
+    let mut s = EditorState::new();
+    type_str(&mut s, "alpha beta");
+
+    s.dispatch_key(
+        FrontendId::LOCAL,
+        key(KeyCode::Backspace, KeyModifiers::CONTROL),
+    );
+    let (text, _, cursor) = probe(&s);
+    assert_eq!(text, "alpha ", "C-BS deletes back through the previous word");
+    assert_eq!(cursor, 6);
+
+    s.dispatch_key(FrontendId::LOCAL, key(KeyCode::Left, KeyModifiers::CONTROL));
+    s.dispatch_key(
+        FrontendId::LOCAL,
+        key(KeyCode::Delete, KeyModifiers::CONTROL),
+    );
+    let (text, _, cursor) = probe(&s);
+    assert_eq!(text, " ", "C-DEL deletes forward through the next word");
+    assert_eq!(cursor, 0);
+}
+
 #[test]
 fn typing_replaces_the_shift_selected_region() {
     let mut s = EditorState::new();