feat: Phase 0 workspace, spikes, and golden harness

Stand up the monorepo skeleton and land the first Phase 0 artifacts:
pairing threat model, plugin catalog, builder detect, 20-prompt golden
harness, and synthetic 2GB mirror timing.

web/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "extends": "../tsconfig.base.json",
+  "compilerOptions": {
+    "jsx": "react-jsx",
+    "outDir": "dist",
+    "rootDir": "src",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "noEmit": true
+  },
+  "include": ["src"]
+}