EANCH-WP-0001 T02: bootstrap standalone TS package + test harness

Add package.json (name evidence-anchor, exports . and ./pdf, scripts
test/typecheck/lint), tsconfig.json (mirrors engine, DOM+jsx), vitest.config.ts
(happy-dom + react plugin), eslint.config.js (confines viewer libs to src/pdf/),
.nvmrc, and placeholder src entrypoints. Depends on @citation-evidence/engine
via sibling-checkout link only; no citation-evidence internals.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tsconfig.json

@@ -0,0 +1,26 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "jsx": "react-jsx",
+    "strict": true,
+    "noImplicitOverride": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedIndexedAccess": true,
+    "exactOptionalPropertyTypes": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "isolatedModules": true,
+    "skipLibCheck": true,
+    "resolveJsonModule": true,
+    "verbatimModuleSyntax": true,
+    "baseUrl": "."
+  },
+  "include": ["src", "vitest.config.ts"],
+  "exclude": ["node_modules", "dist"]
+}