fix: re-apply dynamic modifier parsing for Shift+Enter after upstream sync

Upstream v0.1.21 reverted PR #70. Re-apply:
- isShiftReturn() / isReturn() dynamic CSI modifier bit parsing
- Kitty progressive enhancement (ESC[>1u) alongside xterm modifyOtherKeys
- Clear input when key.return is true (safety net)

Author: dengmik-commits

src/tests/promptInputKeys.test.ts

@@ -80,7 +80,7 @@ test("parseTerminalInput keeps BS payload for meta+backspace", () => {
 
 test("parseTerminalInput recognizes shifted return sequences", () => {
   const { input, key } = parseTerminalInput("\u001B\r");
-  assert.equal(input, "\r");
+  assert.equal(input, "");
   assert.equal(key.return, true);
   assert.equal(key.shift, true);
   assert.equal(key.meta, false);
@@ -108,8 +108,8 @@ test("parseTerminalInput recognizes alternate shifted return sequences", () => {
 });
 
 test("terminal extended key helpers request and restore modifyOtherKeys mode", () => {
-  assert.equal(enableTerminalExtendedKeys(), "\u001B[>4;1m");
-  assert.equal(disableTerminalExtendedKeys(), "\u001B[>4;0m");
+  assert.equal(enableTerminalExtendedKeys(), "\u001B[>4;1m\u001B[>1u");
+  assert.equal(disableTerminalExtendedKeys(), "\u001B[>4;0m\u001B[<u");
 });
 
 test("parseTerminalInput recognizes terminal focus events", () => {

src/ui/prompt/cursor.ts

@@ -41,11 +41,11 @@ function disableTerminalFocusReporting(): string {
 }
 
 export function enableTerminalExtendedKeys(): string {
-  return "\u001B[>4;1m";
+  return "\u001B[>4;1m\u001B[>1u";
 }
 
 export function disableTerminalExtendedKeys(): string {
-  return "\u001B[>4;0m";
+  return "\u001B[>4;0m\u001B[<u";
 }
 
 export function getPromptCursorPlacement(

src/ui/prompt/useTerminalInput.ts

@@ -26,7 +26,42 @@ const BACKSPACE_BYTES = new Set(["\u007F", "\b"]);
 const FORWARD_DELETE_SEQUENCES = new Set(["\u001B[3~", "\u001B[P"]);
 const HOME_SEQUENCES = new Set(["\u001B[H", "\u001B[1~", "\u001B[7~", "\u001BOH"]);
 const END_SEQUENCES = new Set(["\u001B[F", "\u001B[4~", "\u001B[8~", "\u001BOF"]);
-const SHIFT_RETURN_SEQUENCES = new Set(["\u001B\r", "\u001B[13;2u", "\u001B[13;2~", "\u001B[27;2;13~"]);
+const SHIFT_RETURN_SEQUENCES = new Set([
+  "\u001B\r",
+  "\u001B[13;2u",
+  "\u001B[13;1u",
+  "\u001B[13;2~",
+  "\u001B[13;1~",
+  "\u001B[27;2;13~",
+  "\u001B[27;1;13~",
+]);
+
+const CSI_SHIFT_RETURN_RE = /^\u001B\[13;(\d+)[u~]$/;
+const CSI_EXTENDED_SHIFT_RETURN_RE = /^\u001B\[27;(\d+);13~$/;
+
+function isShiftReturn(raw: string): boolean {
+  if (SHIFT_RETURN_SEQUENCES.has(raw)) return true;
+  let m: RegExpMatchArray | null;
+  if ((m = raw.match(CSI_SHIFT_RETURN_RE)) !== null) {
+    const mod = parseInt(m[1], 10);
+    return (mod & 2) !== 0 || (mod & 1) !== 0;
+  }
+  if ((m = raw.match(CSI_EXTENDED_SHIFT_RETURN_RE)) !== null) {
+    const mod = parseInt(m[1], 10);
+    return (mod & 2) !== 0 || (mod & 1) !== 0;
+  }
+  return false;
+}
+
+const CSI_RETURN_RE = /^\u001B\[13;(\d+)[u~]$/;
+const CSI_EXTENDED_RETURN_RE = /^\u001B\[27;(\d+);13~$/;
+
+function isReturn(raw: string): boolean {
+  if (raw === "\r") return true;
+  if (SHIFT_RETURN_SEQUENCES.has(raw)) return true;
+  if (META_RETURN_SEQUENCES.has(raw)) return true;
+  return CSI_RETURN_RE.test(raw) || CSI_EXTENDED_RETURN_RE.test(raw);
+}
 const META_RETURN_SEQUENCES = new Set(["\u001B[13;3u", "\u001B[13;4u"]);
 const CTRL_LEFT_SEQUENCES = new Set(["\u001B[1;5D", "\u001B[5D"]);
 const CTRL_RIGHT_SEQUENCES = new Set(["\u001B[1;5C", "\u001B[5C"]);
@@ -113,10 +148,10 @@ export function parseTerminalInput(data: Buffer | string): { input: string; key:
     end: END_SEQUENCES.has(raw),
     pageDown: raw === "\u001B[6~",
     pageUp: raw === "\u001B[5~",
-    return: raw === "\r" || SHIFT_RETURN_SEQUENCES.has(raw) || META_RETURN_SEQUENCES.has(raw),
+    return: isReturn(raw),
     escape: raw === "\u001B",
     ctrl: CTRL_LEFT_SEQUENCES.has(raw) || CTRL_RIGHT_SEQUENCES.has(raw),
-    shift: SHIFT_RETURN_SEQUENCES.has(raw),
+    shift: isShiftReturn(raw),
     tab: raw === "\t" || raw === "\u001B[Z",
     backspace: BACKSPACE_BYTES.has(raw),
     delete: FORWARD_DELETE_SEQUENCES.has(raw),
@@ -162,7 +197,7 @@ export function parseTerminalInput(data: Buffer | string): { input: string; key:
     key.shift = true;
   }
 
-  if (key.tab || key.backspace || key.delete) {
+  if (key.tab || key.backspace || key.delete || key.return) {
     input = "";
   }