fix: swap High/Low in BasePermissions.set() and has()

[vgrem]

Summary

BasePermissions.set() and has() had High and Low swapped internally:

• Bits 0-31 (lower 32 bits) were stored in self.High
• Bits 32-63 (upper 32 bits) were stored in self.Low

This caused to_json() to serialize values into the wrong API fields — sending Low bits as High and High bits as Low.

Fix

Swapped the field assignments in set() and field checks in has():

  if bit_pos < self._BITS_PER_INT:
-    self.High |= mask
     self.Low |= mask
+    self.High |= mask

- return bool(self.High & mask) if bit_pos < self._BITS_PER_INT else bool(self.Low & mask)
+ return bool(self.Low & mask) if bit_pos < self._BITS_PER_INT else bool(self.High & mask)

to_json() and set_property() are already correct — they just received swapped values.

Example

Before fix:

Permission	Bit	Stored in	JSON output
ViewListItems (bit 0)	Low	self.High	{"Low": 0, "High": 1}
ManageWeb (bit 35)	High	self.Low	{"Low": 8, "High": 0}

After fix:

Permission	Bit	Stored in	JSON output
ViewListItems (bit 0)	Low	self.Low	{"Low": 1, "High": 0}
ManageWeb (bit 35)	High	self.High	{"Low": 0, "High": 8}

Fixes #959

[dksdarkness]

Thank you for fixing it!