feat(cursor): pan glide replaces pan smoothing (#430)

[Maxaubert]

Fixes #430. Stacked on #428 (settings page stack); retarget to main as the stack merges.

Why

Pan smoothing (cursorSmoothing) eased the view toward the pointer: lag, never momentum, and with the Transform engine's DWM centring it did nothing in normal use. What was wanted is inertia.

What

• Removed Pan smoothing everywhere: cursor mapper easing (and its tick-rate/tick-delta plumbing), config key (old key ignored), Settings row, tray flyout slider, the now-unused ValueFmt::Dec2, tests, docs.
• Added Pan glide (panGlideMs, 0-600 ms, default 0 = off, Experimental tag): when the hand stops a quick movement (over 300 desktop px/s over the last ~30 ms), the pointer keeps gliding and slows to rest with that time constant; the view follows by DWM centring, so nothing jumps when the hand takes over. Pure logic in src/pan_glide.h with tests.
• Ends at once on any hand movement or mouse button; off in games (borderless cover), Inspect, detached views (caret, focus, keys), at 1x, and at the monitor edge. Wind's own steps move the tick baseline (lastSetVirtual), so the lock detector and gain learner only see hand motion.
• Takes Pan smoothing's place in View > Speed and in the tray flyout (saved tray orders drop the old key and append the new one).

Tests

• build.bat test: 594 passed (new test_pan_glide.cpp; mapper smoothing tests removed). build.bat, build.bat tray build.
• ui: npx playwright test: 177 passed.
• Field: deployed for hands-on testing with panGlideMs=150.

Feature: minor version bump at merge time.

🤖 Generated with Claude Code

https://claude.ai/code/session_011zPmivSAQeivGUdBjTsaMu