feat: add Vitest test infrastructure for agent and script validation (#337)

Adds Vitest + TypeScript test infrastructure for agent validation. Validates 642 agent files across 14 categories for YAML frontmatter, kebab-case naming, and directory population.

package.json

@@ -0,0 +1,30 @@
+{
+  "name": "agency-agents",
+  "version": "1.0.0",
+  "description": "> **A complete AI agency at your fingertips** - From frontend wizards to Reddit community ninjas, from whimsy injectors to reality checkers. Each agent is a specialized expert with personality, processes, and proven deliverables.",
+  "main": "index.js",
+  "directories": {
+    "example": "examples"
+  },
+  "scripts": {
+    "test": "vitest run"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/msitarzewski/agency-agents.git"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "commonjs",
+  "bugs": {
+    "url": "https://github.com/msitarzewski/agency-agents/issues"
+  },
+  "homepage": "https://github.com/msitarzewski/agency-agents#readme",
+  "devDependencies": {
+    "@types/node": "^25.5.0",
+    "gray-matter": "^4.0.3",
+    "typescript": "^6.0.2",
+    "vitest": "^4.1.1"
+  }
+}