fix: restore Super key activation for tiling mode (regression from 64afeba)

[liuxiaopai-ai]

Problem

Fixes #485 — After updating from v17.2 to v17.3, pressing the Super key while dragging a window no longer triggers tiling mode.

Root Cause

Commit 64afeba (refactor: use Clutter.ModifierType as mask) introduced two issues:

1. Wrong mask for Super key: Clutter.ModifierType.SUPER_MASK (bit 26, value 0x4000000) was used, but global.get_pointer() returns MOD4_MASK (bit 6, value 64) for the Super key. These are different bit positions in the modifier bitmask — SUPER_MASK is a GDK4-style semantic mask, while MOD4_MASK is what Clutter/Mutter actually reports at runtime.

2. Overly strict comparison: The check was changed from (modifier & mask) !== 0 to (modifier & mask) === mask. The strict equality fails when additional modifier bits are set alongside the target key (which commonly happens with Super).

The old magic numbers (val = 2, 3, 6 as bit positions) happened to be correct: 1 << 6 = 64 = MOD4_MASK, which matches what global.get_pointer() returns for Super.

Fix

• Use Clutter.ModifierType.MOD4_MASK instead of SUPER_MASK for the Super key
• Restore !== 0 comparison for robustness (matches behavior of other modifier checks in the codebase, e.g., hoverLine.ts and layoutEditor.ts)

This preserves the intent of 64afeba (using named enum constants instead of magic numbers) while fixing the regression.

[domferr]

Hi, thanks a million!