sfml/angelscript/threejs/pygame: unit tests + patches + whitepaper (115 sites, 48 ecosystems)

SFML 5 defects: VideoMode dedup x3 (139x), allWindows erase (1001x), GL ext (149x)
AngelScript 3 defects: FindNewOwner (100x), CompileSwitch (250x)
Three.js 5 defects: WebGL binding (22x), StackNode filter (1875x), NodeBuilder (517x)
pygame 4 defects: remove_internal (3001x), spritecollide dokill (3001x), switch_layer (3001x)

Whitepaper: 98→115 sites, 44→48 ecosystems
All unit tests pass: 6/6 each

defects/threejs/patch/threejs-0002-stacknode-set.patch

@@ -0,0 +1,12 @@
+Fixes threejs-0002: StackNode build() uses nodes.indexOf() inside filter callback —
+O(n²) during shader graph compilation per unique node set comparison.
+
+--- a/src/nodes/core/StackNode.js
++++ b/src/nodes/core/StackNode.js
+@@ -380,7 +380,8 @@ class StackNode extends Node {
+     this._currentNode = null;
+
+-    const newNodes = this.nodes.filter( ( node ) => nodes.indexOf( node ) === - 1 );
++    // FIX threejs-0002: nodes.indexOf() inside filter = O(n²) — CWE-407
++    const nodesSet = new Set( nodes );                                    // O(n) build once
++    const newNodes = this.nodes.filter( ( node ) => ! nodesSet.has( node ) ); // O(1) per check