fix(windows): hide console flashes in GUI-reachable exec paths and provider transports (#56747)

Six spawn sites reachable from the desktop GUI / TUI gateway lacked CREATE_NO_WINDOW, so a windowless parent (pythonw/Electron) flashed a conhost per spawn: cli.exec RPC, quick-commands exec dispatch, and shell.exec RPC in tui_gateway/server.py; the CLI REPL quick-commands exec in cli.py; and the per-session provider transports in agent/copilot_acp_client.py and agent/transports/codex_app_server.py (Popen, hide-only so PIPE stdio stays intact).

All use hermes_cli._subprocess_compat.windows_hide_flags() (no-op on POSIX), matching the pattern already used at three other sites in tui_gateway/server.py. Deliberately hide-only — no detach flags, no Electron changes (per the #54220 revert history).

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

agent/copilot_acp_client.py

@@ -503,6 +503,10 @@ class CopilotACPClient:
 
     def _run_prompt(self, prompt_text: str, *, timeout_seconds: float) -> tuple[str, str]:
         try:
+            # Hide the console the CLI child would otherwise flash on Windows
+            # (#56747). Hide-only — stdio pipes stay intact for the ACP wire.
+            from hermes_cli._subprocess_compat import windows_hide_flags
+
             proc = subprocess.Popen(
                 [self._acp_command] + self._acp_args,
                 stdin=subprocess.PIPE,
@@ -512,6 +516,7 @@ class CopilotACPClient:
                 bufsize=1,
                 cwd=self._acp_cwd,
                 env=_build_subprocess_env(),
+                creationflags=windows_hide_flags(),
             )
         except FileNotFoundError as exc:
             raise RuntimeError(

agent/transports/codex_app_server.py

@@ -127,6 +127,10 @@ class CodexAppServerClient:
         # Codex emits tracing to stderr; default WARN keeps it quiet for users.
         spawn_env.setdefault("RUST_LOG", "warn")
 
+        # Hide the console the codex child would otherwise flash on Windows
+        # (#56747). Hide-only — stdio pipes stay intact for the app-server wire.
+        from hermes_cli._subprocess_compat import windows_hide_flags
+
         self._proc = subprocess.Popen(
             cmd,
             stdin=subprocess.PIPE,
@@ -134,6 +138,7 @@ class CodexAppServerClient:
             stderr=subprocess.PIPE,
             bufsize=0,
             env=spawn_env,
+            creationflags=windows_hide_flags(),
         )
         self._next_id = 1
         self._pending: dict[int, _Pending] = {}

cli.py

@@ -9481,9 +9481,12 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin, CLIBillingMixin):
                             # has all API keys in os.environ.
                             from tools.environments.local import _sanitize_subprocess_env
                             sanitized_env = _sanitize_subprocess_env(os.environ.copy())
+                            from hermes_cli._subprocess_compat import windows_hide_flags
                             result = subprocess.run(
                                 exec_cmd, shell=True, capture_output=True,
-                                text=True, timeout=30, env=sanitized_env
+                                text=True, timeout=30, env=sanitized_env,
+                                # No console flash on Windows (#56747).
+                                creationflags=windows_hide_flags(),
                             )
                             output = result.stdout.strip() or result.stderr.strip()
                             if output:

tui_gateway/server.py

@@ -13841,6 +13841,10 @@ def _(rid, params: dict) -> dict:
     if hint:
         return _ok(rid, {"blocked": True, "hint": hint, "code": -1, "output": ""})
     try:
+        # CREATE_NO_WINDOW on Windows — under the desktop GUI's windowless
+        # parent, this spawn otherwise flashes a console (#56747).
+        from hermes_cli._subprocess_compat import windows_hide_flags
+
         r = subprocess.run(
             [sys.executable, "-m", "hermes_cli.main", *argv],
             capture_output=True,
@@ -13851,6 +13855,7 @@ def _(rid, params: dict) -> dict:
             # needs provider credentials. Tier-1 secrets still stripped (#29157).
             env=hermes_subprocess_env(inherit_credentials=True),
             stdin=subprocess.DEVNULL,
+            creationflags=windows_hide_flags(),
         )
         parts = [r.stdout or "", r.stderr or ""]
         out = "\n".join(p for p in parts if p).strip() or "(no output)"
@@ -13910,6 +13915,8 @@ def _(rid, params: dict) -> dict:
             # has all API keys in os.environ.
             from tools.environments.local import _sanitize_subprocess_env
             sanitized_env = _sanitize_subprocess_env(os.environ.copy())
+            from hermes_cli._subprocess_compat import windows_hide_flags
+
             r = subprocess.run(
                 qc.get("command", ""),
                 shell=True,
@@ -13918,6 +13925,7 @@ def _(rid, params: dict) -> dict:
                 timeout=30,
                 stdin=subprocess.DEVNULL,
                 env=sanitized_env,
+                creationflags=windows_hide_flags(),
             )
             output = (
                 (r.stdout or "")
@@ -16984,9 +16992,12 @@ def _(rid, params: dict) -> dict:
     except ImportError:
         return _err(rid, 5001, "shell.exec unavailable: approval safety module not importable")
     try:
+        from hermes_cli._subprocess_compat import windows_hide_flags
+
         r = subprocess.run(
             cmd, shell=True, capture_output=True, text=True, timeout=30, cwd=os.getcwd(),
             stdin=subprocess.DEVNULL,
+            creationflags=windows_hide_flags(),
         )
         return _ok(
             rid,