fix: normalise \r\n and \r line endings in pasted text

Windows (CRLF) and old Mac (CR) line endings are normalised to LF
before the 5-line collapse threshold is checked in handle_paste.

Without this, markdown copied from Windows sources contains \r\n but
the line counter (pasted_text.count('\n')) still works — however
buf.insert_text() leaves bare \r characters in the buffer which some
terminals render by moving the cursor to the start of the line,
making multi-line pastes appear as a single overwritten line.

cli.py

@@ -7010,6 +7010,9 @@ class HermesCLI:
             buffer.
             """
             pasted_text = event.data or ""
+            # Normalise line endings — Windows \r\n and old Mac \r both become \n
+            # so the 5-line collapse threshold and display are consistent.
+            pasted_text = pasted_text.replace('\r\n', '\n').replace('\r', '\n')
             if self._try_attach_clipboard_image():
                 event.app.invalidate()
             if pasted_text: