fix: create pgadmin4.log with mode 0o600

Override EnhancedRotatingFileHandler._open() so the active log file
and rotated backups are created owner-only on POSIX. The parent
DATA_DIR is already 0o700, so this is defense-in-depth — but the
log file can contain sensitive context (auth events, query
fragments, paths) and should not be world/group readable on its own.

Pre-existing log files keep their current permissions; new installs
and rotated files pick up the tighter mode. Windows uses the default
open path since os.open mode is ignored there.

web/pgadmin/utils/enhanced_log_rotation.py

@@ -7,6 +7,7 @@
 #
 ##########################################################################
 
+import os
 import re
 from logging import handlers
 
@@ -46,6 +47,20 @@ class EnhancedRotatingFileHandler(handlers.TimedRotatingFileHandler,
                                               backupCount=backup_count,
                                               encoding=encoding)
 
+    # Create new log files with mode 0o600 so they are not world/group
+    # readable. Pre-existing files keep their permissions; the parent
+    # DATA_DIR is already 0o700 on POSIX, so this is defense-in-depth.
+    # On Windows the mode arg to os.open is ignored — fall back to the
+    # default behavior there.
+    def _open(self):
+        if os.name == 'nt':
+            return super()._open()
+        flags = os.O_WRONLY | os.O_CREAT | (
+            os.O_APPEND if self.mode == 'a' else os.O_TRUNC)
+        fd = os.open(self.baseFilename, flags, 0o600)
+        return os.fdopen(fd, self.mode, encoding=self.encoding,
+                         errors=getattr(self, 'errors', None))
+
     # Time & Size combined rollover
     def shouldRollover(self, record):
         return handlers.TimedRotatingFileHandler.shouldRollover(self, record) \