fix(scroll): enable pixel-scroll-precision-mode for smooth macOS trackpad scrolling

Replace mwheel.el fallback with pixel-scroll-precision-mode (Emacs 29+).
Works on NS/Cocoa builds — previous comment was wrong.

- ns-use-mwheel-momentum t: pass through macOS kinetic scroll events
- pixel-scroll-precision-use-momentum nil: avoid double-momentum (macOS
  already handles inertia; Emacs simulation would stack on top)
- pixel-scroll-precision-large-scroll-height 40.0: reasonable page-jump size
- Removed global-set-key mwheel-scroll overrides (were blocking precision mode)
- Kept mouse-wheel-follow-mouse + mouse-wheel-tilt-scroll for horizontal

config.el

@@ -180,22 +180,23 @@ Bound to cmd+v in org-mode and markdown-mode."
     (global-set-key key #'ignore))
   (setq mouse-highlight nil))
 
-;; macOS scroll wheel best practice (NS/Cocoa build):
-;; - pixel-scroll-precision-mode is NOT used: it targets X11/Haiku and breaks
-;;   NS/Cocoa scroll event delivery (rebinds [wheel-up/down] to non-working handlers)
-;; - Standard mwheel.el with conservative settings is reliable on macOS
-;; - NS backend converts trackpad + physical wheel to [wheel-up]/[wheel-down] events
+;; macOS smooth scrolling — pixel-scroll-precision-mode (Emacs 29+, works on NS/Cocoa)
+;; pixel-scroll-precision-mode handles [wheel-up/down] → pixel-scroll-precision.
+;; ns-use-mwheel-momentum: macOS sends momentum-phase events after finger lift;
+;;   setting t passes them through so kinetic/inertial scrolling works.
+;; pixel-scroll-precision-use-momentum nil: let macOS handle momentum (Emacs
+;;   momentum simulation would double-apply on top of NS momentum events).
 (when (display-graphic-p)
-  (require 'mwheel)
-  ;; 3 lines per scroll tick; shift = 1 line; no progressive acceleration
-  (setq mouse-wheel-scroll-amount    '(3 ((shift) . 1) ((meta) . 0) ((control) . text-scale))
-        mouse-wheel-progressive-speed nil   ; constant speed, no acceleration
-        mouse-wheel-follow-mouse      t     ; scroll window under cursor
-        mouse-wheel-tilt-scroll       t     ; horizontal scroll with tilt/two-finger
-        mouse-wheel-flip-direction    nil)  ; standard direction (not natural)
-  ;; Ensure mwheel-scroll is bound (Doom may remap these)
-  (global-set-key [wheel-up]   #'mwheel-scroll)
-  (global-set-key [wheel-down] #'mwheel-scroll))
+  ;; NS/macOS: honour trackpad kinetic (inertial) scrolling
+  (setq ns-use-mwheel-momentum t)
+  ;; Horizontal scroll + follow-mouse still go through mwheel.el
+  (setq mouse-wheel-follow-mouse t
+        mouse-wheel-tilt-scroll  t)
+  ;; Pixel-precise vertical scrolling (Emacs 29+)
+  (when (fboundp 'pixel-scroll-precision-mode)
+    (setq pixel-scroll-precision-use-momentum nil  ; macOS provides its own momentum
+          pixel-scroll-precision-large-scroll-height 40.0)
+    (pixel-scroll-precision-mode 1)))