Add VitePress documentation site with complete user guides

Covers getting started, repositories, scanning, findings, configuration,
SBOM, code graph, impact analysis, DAST, AI chat, issue tracker integration,
Docker deployment, environment variables, Keycloak auth, and OpenTelemetry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "compliance-scanner-docs",
+  "private": true,
+  "scripts": {
+    "dev": "vitepress dev",
+    "build": "vitepress build",
+    "preview": "vitepress preview"
+  },
+  "devDependencies": {
+    "vitepress": "^1.6.4"
+  }
+}