Shader graph: UV, Sample texture, Texture size, Time, Sin/Floor/Fract/Step; edge mode on Output (#78)

Fragment-side coordinate nodes instead of vertex nodes: the quad stays the
quad, a UV read plus a sample at a computed coordinate covers flip, scroll,
wave, pixelate and scanlines. Time is a uniform only when a Time node reaches
the Output; a viewport that drew a Time shader redraws from the ticker so the
Scene tab animates without a running world. Edge (Mirror/Repeat/Clamp) is a
second texture variant in TextureLibrary because WebGL binds no TextureStyle
resource of the shader. The compiler now emits #version 300 es first: Pixi
only compiles as ES 3.00 when the fragment says so, and textureSize needs it.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/editor/debugHook.ts

@@ -3,6 +3,7 @@ import { resolveObjects } from '../core/model/instance';
 import { findObjectHolder } from '../core/model/Project';
 import type { FrameRect } from '../core/model/texture';
 import { activeDrag, Button, ui, Widget } from '../ui';
+import { shaderLibrary } from '../viewport/ShaderLibrary';
 import { textureLibrary } from '../viewport/TextureLibrary';
 import type { CentreTab, Editor } from './Editor';
 import { currentImagePicker } from './texture/ImagePicker';
@@ -410,6 +411,10 @@ export function installDebugHook(app: Application, state: EditorState, editor: E
       walk(app.stage);
       return n;
     },
+    /** Holds the shader clock at `at` seconds, so a Time shader's pixels can be measured; null releases it. */
+    shaderTime: (at: number | null) => shaderLibrary.freezeTime(at),
+    /** Which views redraw every tick because a Time shader is on screen. */
+    animates: () => ({ scene: viewport.animates, game: gameView.animates }),
     lowLatency: () =>
       (app.renderer as unknown as { gl?: WebGL2RenderingContext }).gl?.getContextAttributes()
         ?.desynchronized === true,