Fix missing /usr/local/CyberCP/bin/python for cron and IncBackups

Add plogical/cyberpanel_python.py with resolve_cyberpanel_python() and
ensure_cyberpanel_bin_python_shim() (symlink to system Python when venv
binary is absent). Call shim before writing root crontab on install/upgrade,
and from IncBackups/IncScheduler.py so existing jobs self-heal. IncBackups
views use resolved interpreter for backupUtilities. Upgrade._python_for_manage
delegates to resolve_cyberpanel_python().

plogical/cyberpanel_python.py

@@ -0,0 +1,67 @@
+# -*- coding: utf-8 -*-
+"""
+Resolve the Python interpreter for CyberPanel CLI and cron jobs.
+
+Some installs omit /usr/local/CyberCP/bin/python (no venv). We symlink that path
+to a working interpreter when missing so existing crontab lines keep working.
+"""
+from __future__ import annotations
+
+import os
+
+_CANDIDATES = (
+    "/usr/local/CyberPanel/bin/python",
+    "/usr/local/CyberCP/bin/python",
+    "/usr/bin/python3",
+    "/usr/local/bin/python3",
+)
+
+
+def resolve_cyberpanel_python() -> str:
+    """Return first existing executable candidate, else /usr/bin/python3."""
+    for path in _CANDIDATES:
+        if path == "/usr/local/CyberCP/bin/python":
+            continue
+        if path and os.path.isfile(path) and os.access(path, os.X_OK):
+            return path
+    return "/usr/bin/python3"
+
+
+def ensure_cyberpanel_bin_python_shim() -> None:
+    """
+    If /usr/local/CyberCP/bin/python is missing or a broken symlink, replace with
+    symlink to resolve_cyberpanel_python(). Non-destructive for a real venv file.
+    """
+    bin_dir = "/usr/local/CyberCP/bin"
+    legacy = os.path.join(bin_dir, "python")
+    try:
+        os.makedirs(bin_dir, exist_ok=True)
+    except OSError:
+        return
+
+    if os.path.isfile(legacy) and os.access(legacy, os.X_OK) and not os.path.islink(legacy):
+        return
+
+    if os.path.islink(legacy):
+        real = os.path.realpath(legacy)
+        if os.path.isfile(real) and os.access(real, os.X_OK):
+            return
+        try:
+            os.unlink(legacy)
+        except OSError:
+            return
+
+    if os.path.lexists(legacy):
+        try:
+            os.remove(legacy)
+        except OSError:
+            try:
+                os.unlink(legacy)
+            except OSError:
+                return
+
+    target = resolve_cyberpanel_python()
+    try:
+        os.symlink(target, legacy)
+    except OSError:
+        pass