added Type Jam puzzle app for review (#1554)

* added Type Jam puzzle app for review

* pr round 2 prep

* updated ci scripts for varfont_shader_puzzle

* resolved unused and minor variable naming issues

* rotator tiles row and col are final vars now

* removed unused import and print from production

* made constructors const where needed

* pages_flow export refactored to directly come from that file

* removed old api commented out section from FragmentShaded

* updated pubspec yaml to correct project name

* dart min version updated; removed unnecessary commented out dependencies from pubspec.yaml

* updated pubspec.yaml min flutter version to ensure FragmentShader support

* added/edited comments for explanation, esp on var fonts; removed obsolete comments

* trailing newline added to pubspec.yaml eof

experimental/varfont_shader_puzzle/shaders/row_offset.frag

@@ -0,0 +1,35 @@
+// Copyright 2023 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#define PI 3.1415926538
+
+layout(location = 0) uniform float uTime;
+layout(location = 1) uniform vec2 uSize;
+layout(location = 3) uniform float uDampener;
+
+layout(location = 0) out vec4 fragColor;
+
+layout(location = 2) uniform sampler2D uTexture;
+
+void main()
+{
+  float piTime = uTime * PI * 2;
+  
+  vec2 texCoord = gl_FragCoord.xy / uSize.xy;
+  
+  float levels = 5;
+  float maxMag = 0.1;
+  float minMag = 0.02;
+  float magMod = maxMag / levels;
+  float row = floor(texCoord.y * uSize.y * 0.25); // resolution/density of rows
+  float offsetDir = mod(row, 2) == 0 ? -1 : 1;
+  float sinFn = cos(texCoord.y * 1 * PI + piTime);
+  float offset = (offsetDir * (minMag + maxMag * sinFn)) * uDampener;
+
+  vec2 offsetTexCoord = vec2(texCoord.x + offset, texCoord.y);
+  vec4 outColor = texture(uTexture, offsetTexCoord);
+  if (texCoord.x + offset < 0.0 || texCoord.x + offset > 1.0) {
+    outColor = vec4(0.0, 0.0, 0.0, 0.0);
+  }
+  fragColor = outColor;
+}