aiorepl: Fix Enter key handling in raw terminal mode.

Handle both CR (0x0D) and LF (0x0A) for command execution to ensure
compatibility with raw terminal mode where Enter sends CR instead of LF.

This fixes the issue where aiorepl required Ctrl+Enter instead of
just Enter to execute commands when used with MicroPython ports that
put stdin in raw mode (such as the updated unix port using pyexec).

Also improves handling of various newline sequences (CRLF, double-LF,
double-CR) to prevent double-execution of commands.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: pi-anl

micropython/aiorepl/aiorepl.py

@@ -119,16 +119,20 @@ async def task(g=None, prompt="--> "):
                 pt = t  # save previous time
                 t = time.ticks_ms()
                 if c < 0x20 or c > 0x7E:
-                    if c == 0x0A:
-                        # LF
+                    if c == 0x0A or c == 0x0D:
+                        # LF or CR (handle both for raw terminal mode compatibility)
                         if paste:
+                            # In paste mode, preserve the actual character
                             sys.stdout.write(b)
                             cmd += b
                             continue
-                        # If the previous character was also LF, and was less
-                        # than 20 ms ago, this was likely due to CRLF->LFLF
-                        # conversion, so ignore this linefeed.
-                        if pc == 0x0A and time.ticks_diff(t, pt) < 20:
+                        # Handle various newline sequences to avoid double-execution:
+                        # - CR+LF (Windows style): ignore LF if it follows CR quickly
+                        # - LF+LF (PTY double-newline): ignore second LF if it follows quickly
+                        # - CR+CR (potential double-CR): ignore second CR if it follows quickly
+                        if ((c == 0x0A and pc == 0x0D) or  # LF after CR (CRLF)
+                            (c == 0x0A and pc == 0x0A) or  # LF after LF (double LF)
+                            (c == 0x0D and pc == 0x0D)) and time.ticks_diff(t, pt) < 20:  # CR after CR
                             continue
                         if curs:
                             # move cursor to end of the line