Complete SDD specification documents

- SPEC.md: Full project specification including scope, objectives, constraints,
  architecture overview, API integration, certificate management, UI structure,
  error handling, audit logging, and out-of-scope items

- REQUIREMENTS.md: Functional requirements (host mgmt, patch monitoring,
  deployment, scheduling, reporting, user mgmt), non-functional requirements
  (security, performance, scalability, reliability, usability), interface
  requirements, data requirements, HIPAA/PCI-DSS compliance

- ARCHITECTURE.md: Architecture decisions, system architecture diagram,
  component design (Axum web server, background worker, PostgreSQL, React SPA,
  internal CA), data flows, technology stack, security architecture,
  deployment architecture, integration points, monitoring

.gitignore

@@ -0,0 +1,14 @@
+# Agent Zero project data
+.a0proj/
+
+# Python environments & cache
+venv/**
+**/__pycache__/**
+
+# Node.js dependencies
+**/node_modules/**
+**/.npm/**
+
+# IDE
+.vscode/
+.idea/