fix: adjust trackpad detection and wheel zoom scaling

[viazovskyi585]

Summary

On Chrome/Edge for Windows, ctrl+wheel zooms in but does nothing on zoom-out. The fix is in core so both the Vue and React wrappers pick it up.

Should be related to #1

Root cause

Two things compounded:

1. detectTrackpad misclassified Windows wheel. It returned true whenever deltaMode === 0 (pixel mode). Chromium on Windows reports mouse-wheel events in pixel mode with deltaY = ±100 (or ±120) per notch, so a regular mouse was treated as a trackpad.

2. The zoom math then broke for the zoom-out direction. With isTrackpad = true, handleWheel skipped its ±100 → ±1 mouse normalization, leaving deltaY = 100. Combined with the trackpad zoomSpeed = 0.01.

Zoom-in had scaleFactor = 2 and still worked, just over-aggressively.

Changes

• core/src/helpers.ts - detectTrackpad Pixel mode alone isn't enough on Windows. Added a magnitude check: trackpads send small deltas (usually under ~30), mouse wheels send chunks of ~100+ per notch. A 50px threshold sits comfortably in between. Line/page mode remains an unconditional mouse signal. The previous comment about avoiding the legacy wheelDeltaY / deltaY === -3 ratio still applies - momentum-scroll deltas stay small, so the magnitude check keeps them classified as trackpad.

• core/src/zoompinch.ts - handleWheel Defensive cap on the per-event zoom multiplier:

const cappedDelta = clamp(-deltaY * zoomSpeed, -0.5, 0.5);
const scaleFactor = 1 + cappedDelta;

Test plan

• Windows + mouse wheel: ctrl+wheel zooms both in and out
• macOS trackpad: pinch / two-finger ctrl-scroll still zooms smoothly, no jumps during momentum
• macOS mouse wheel: still zooms
• Windows trackpad (precision touchpad): still zooms
• Pan is unchanged on all of the above

Need some help testing coz i don't have any windows/linux laptop.