feat: expand module workflows, dynamic config, notifications and console API

src/gyxx_flow/workflow/steps.py

@@ -14,7 +14,10 @@ from typing import IO, Mapping
 import psutil
 
 from gyxx_flow.core.context import RunContext
-from gyxx_flow.core.exit_codes import COOKIE_SKIP_EXIT_CODE
+from gyxx_flow.core.exit_codes import (
+    COOKIE_SKIP_EXIT_CODE,
+    IDEMPOTENT_REPLAY_EXIT_CODE,
+)
 from gyxx_flow.core.text import bounded_head_tail
 
 _CREATE_SUSPENDED = 0x00000004
@@ -226,6 +229,15 @@ class CommandStep:
                 reason="cookie-preflight",
             )
 
+        if return_code == IDEMPOTENT_REPLAY_EXIT_CODE:
+            return StepExecution(
+                exit_code=return_code,
+                stdout=stdout,
+                stderr=stderr,
+                skipped=True,
+                reason="idempotent-replay",
+            )
+
         error = None
         if return_code != 0:
             error = _command_failure_detail(
@@ -249,9 +261,16 @@ def _start_process(
     stdout: IO[str],
     stderr: IO[str],
 ) -> tuple[subprocess.Popen[str], _WindowsJob | None]:
+    effective_env = dict(env)
+    if os.name == "nt":
+        # Python launched with redirected stdio can otherwise inherit the
+        # Windows ANSI code page (typically GBK), while the parent streams
+        # are opened as UTF-8.  Keep child diagnostics readable in journals
+        # and the console, especially for Chinese business errors.
+        effective_env.setdefault("PYTHONIOENCODING", "utf-8")
     common = {
         "cwd": cwd,
-        "env": env,
+        "env": effective_env,
         "shell": False,
         "stdout": stdout,
         "stderr": stderr,