Menu: touch swipe-to-scroll with tap disambiguation, fling, wider scrollbar

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

HANDOFF.md

@@ -155,6 +155,13 @@ TERMINOLOGY (owner-corrected — use precisely):
   on owner gain/loss; owner's stick Y beyond 0.3 → wheel notches at 14/s (`WheelUp/Down`, press +
   release). Cursor dot per hand (touch: blue, shrinks as the tip nears; laser: orange; non-owner
   half-transparent). Buttons fire on release (Godot default) = tap semantics.
+  **Swipe vs tap (owner: scrollbar too small to grab, 2026-10-02)**: a touch landing on a
+  vertically scrollable `ScrollContainer` (found by walking up from `GuiGetHoveredControl()`; a
+  `Range` — slider/scrollbar — on the way keeps the immediate press) is held back. Tip travel
+  > `SwipeThreshold` 16 px (~6 mm) before release = swipe: `ScrollVertical` follows the tip,
+  release flings (velocity smoothed at 30/s, decay `FlingDecay` 5/s, stops below 30 px/s or at an
+  end), and NO click is sent. Released sooner = tap: motion + press + release sent together at
+  the contact point. While held back, mouse events carry no button mask.
 - **MainMenu.cs** — the menu content (`PanelContainer`, built in code, own `Theme`: 26 px font,
   64 px buttons ≈ 24 mm, round 36 px slider grabber, wide scrollbar, hover/pressed styles, no focus
   boxes). Header: title, FPS (4 Hz), Close. Tabs: **Player** (Return to spawn, Recalibrate body),
@@ -169,7 +176,8 @@ TERMINOLOGY (owner-corrected — use precisely):
   Return-to-spawn fires once while the other hand idles as a laser = arbitration), side entry
   behind the surface does NOT press, laser + trigger (tab switch, Reset props, laser distance),
   held trigger arriving does NOT click, touch tab switch, laser slider drag, thumbstick scroll of
-  the log, Recalibrate disabled without / enabled + called with a stub "calibration" node, header
+  the log, touch swipe scrolls with no click, fast swipe flings, a jittery tap on a button inside
+  the log still clicks, the scrollbar itself still drags, Recalibrate disabled without / enabled + called with a stub "calibration" node, header
   Close by touch. Must print "MENU: overall PASS".
 - **TeleportMarker.cs** — `scenes/teleport_marker.tscn`: disc + beam + Label3D, group
   "teleport_marker", StaticBody pick box. `SetNear` hides visuals, `SetHighlighted` swaps colors.
@@ -396,7 +404,7 @@ Floor StaticBody mask 1|3|4|5 (collision_mask 29).
   in-headset: text sharpness/shimmer at normal distance (no mipmaps — if it shimmers when far,
   lower the resolution or try `SubViewportCompositionLayer`; if blurry up close, raise
   `SizePixels`), touch press depth/feel (`ContactDepth`/`ReleaseDepth`), accidental presses when
-  reaching through the panel, laser/touch hand-over near the panel, thumbstick scroll direction,
+  reaching through the panel, laser/touch hand-over near the panel, thumbstick scroll direction, swipe threshold/fling feel,
   the stylus tip vs the drawn cursor dot alignment, and whether 0.3 m summon distance is in reach.
 - **Locomotion direction undecided** — owner's lean: full physics thumbstick movement if
   the body track goes the Nimso way (stick pushes the physics body; sway/jog detection