Client Commands: telegram-panel slash commands with Discord-style parameters

Lists the panel account's client commands as Telegram slash commands (hourly
refresh, cached on the device), shows their parameters while typing, runs
complete commands on the panel instead of sending them and shows the answer
as an "Only visible to you" message (latest 20 kept in memory). Holding send
offers Run / Send as message / Send response in chat (red ! badge); an
answer's menu starts with Send in chat. Other plugins register their own
commands through the client_commands library module.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/diag.py

@@ -0,0 +1,54 @@
+"""Diagnostics mirrored to a file, since this device's logcat surfaces neither
+Chaquopy stdout nor android_utils.log output.
+
+The file lives under `get_files_dir()` (app external storage), so it is
+readable over adb:
+  adb shell cat "/sdcard/Android/data/com.exteragram.messenger/files/exteraGram/exteraGram Files/client_commands/diag.log"
+"""
+
+import os
+import time
+import traceback
+
+_MAX_BYTES = 256 * 1024
+_path = None
+
+
+def _file():
+    global _path
+    if _path is None:
+        try:
+            from file_utils import get_files_dir
+
+            directory = os.path.join(get_files_dir(), "client_commands")
+            os.makedirs(directory, exist_ok=True)
+            _path = os.path.join(directory, "diag.log")
+        except Exception:
+            _path = ""
+    return _path
+
+
+def log(message):
+    line = time.strftime("%H:%M:%S ") + str(message)
+    try:
+        from android_utils import log as android_log
+
+        android_log("[client_commands] " + line)
+    except Exception:
+        pass
+    path = _file()
+    if not path:
+        return
+    try:
+        mode = "a"
+        if os.path.exists(path) and os.path.getsize(path) > _MAX_BYTES:
+            mode = "w"
+        with open(path, mode, encoding="utf-8") as handle:
+            handle.write(line + "\n")
+    except Exception:
+        pass
+
+
+def error(where, exc=None):
+    detail = traceback.format_exc() if exc is not None else ""
+    log(f"ERROR {where}: {exc!r}\n{detail}")