fix: PDF finger ink, chrome UX, OneNote pens, and pen physics

Wire finger drawing on PDF without breaking pinch; auto-hide page scrubber and fix bounce; share sticky tools with resize and per-page remember; side-button select; separate pen slots with colors; rnote pressure shapes plus tip-velocity width and lower stroke latency.

Co-authored-by: Cursor <cursoragent@cursor.com>

test/pressure_curve_test.dart

@@ -1,5 +1,7 @@
 // Tests for the configurable pen-pressure response (F5).
 
+import 'dart:math' as math;
+
 import 'package:flutter_test/flutter_test.dart';
 
 import 'package:badnote/editor/input/pressure_curve.dart';
@@ -46,4 +48,59 @@ void main() {
     // Even a light touch stays near full width.
     expect(marker.apply(0.1), greaterThan(0.9));
   });
+
+  group('PressureCurve.shaped', () {
+    const floor = 0.1;
+
+    test('every shape maps 0→floor and 1→1', () {
+      for (final shape in PressureCurveShape.values) {
+        final c = PressureCurve.shaped(shape, floor: floor);
+        expect(c.apply(0.0), closeTo(floor, 1e-9), reason: '$shape at 0');
+        expect(c.apply(1.0), closeTo(1.0, 1e-9), reason: '$shape at 1');
+      }
+    });
+
+    test('midpoints differ across shapes', () {
+      final mids = {
+        for (final shape in PressureCurveShape.values)
+          shape: PressureCurve.shaped(shape).apply(0.5),
+      };
+      expect(mids[PressureCurveShape.linear], closeTo(0.5, 1e-9));
+      expect(mids[PressureCurveShape.soft], closeTo(math.pow(0.5, 0.6), 1e-9));
+      expect(mids[PressureCurveShape.quadratic], closeTo(0.25, 1e-9));
+      expect(mids[PressureCurveShape.cubic], closeTo(0.125, 1e-9));
+      expect(mids[PressureCurveShape.sqrt], closeTo(math.sqrt(0.5), 1e-9));
+      final logMid = math.log(1 + kLogarithmicPressureK * 0.5) /
+          math.log(1 + kLogarithmicPressureK);
+      expect(mids[PressureCurveShape.logarithmic], closeTo(logMid, 1e-9));
+
+      // Soft (γ<1) > linear > quadratic > cubic at p=0.5; log is above linear.
+      expect(mids[PressureCurveShape.soft]! > mids[PressureCurveShape.linear]!,
+          isTrue);
+      expect(
+          mids[PressureCurveShape.linear]! >
+              mids[PressureCurveShape.quadratic]!,
+          isTrue);
+      expect(
+          mids[PressureCurveShape.quadratic]! >
+              mids[PressureCurveShape.cubic]!,
+          isTrue);
+      expect(
+          mids[PressureCurveShape.logarithmic]! >
+              mids[PressureCurveShape.linear]!,
+          isTrue);
+      // Distinct midpoints (no two shapes collide at p=0.5).
+      expect(mids.values.toSet().length, PressureCurveShape.values.length);
+    });
+
+    test('shaped presets set expected gamma (except log)', () {
+      expect(PressureCurve.shaped(PressureCurveShape.linear).gamma, 1.0);
+      expect(PressureCurve.shaped(PressureCurveShape.soft).gamma, 0.6);
+      expect(PressureCurve.shaped(PressureCurveShape.quadratic).gamma, 2.0);
+      expect(PressureCurve.shaped(PressureCurveShape.cubic).gamma, 3.0);
+      expect(PressureCurve.shaped(PressureCurveShape.sqrt).gamma, 0.5);
+      expect(PressureCurve.shaped(PressureCurveShape.logarithmic).shape,
+          PressureCurveShape.logarithmic);
+    });
+  });
 }