Add comprehensive code comments throughout

[JoshuaAFerguson]

Add extensive package-level documentation and JSDoc comments to improve code maintainability and developer experience across the StreamSpace project.

API Backend (42 files):

• Add comprehensive package docs to 19 handler files (users, groups, teams, catalog, dashboard, monitoring, activity, notifications, search, etc.)
• Add detailed security-focused docs to 9 middleware files (compression, input validation, session management, timeout, webhook, etc.)
• Add authentication documentation to 5 auth files (handlers, middleware, OIDC, providers, token hashing)
• Add infrastructure docs to 9 files (database layer, cache, k8s client, errors, websocket)

Documentation includes:

• Purpose and responsibilities
• Security considerations and attack mitigations
• Implementation details and architecture patterns
• Thread safety guarantees
• API endpoints and route mappings
• Example usage with code snippets
• Dependencies and integrations

Web UI (44 files):

• Add comprehensive JSDoc to 22 React components (Plugin*, Session*, Template*, Repository*, Quota*, Rating*, WebSocket*, etc.)
• Add JSDoc to 14 user pages (Dashboard, Sessions, Catalog, Plugins, Repositories, Scheduling, Login, etc.)
• Add JSDoc to 8 admin pages (Dashboard, Users, Plugins, Quotas, Scaling, Integrations, Compliance)

JSDoc includes:

• Component/page purpose and features
• Props documentation with types
• Route paths and access control (@page, @route, @access)
• User workflows and use cases
• Real-time WebSocket features
• Example usage with route configuration
• Cross-references to related components

All documentation follows established patterns:

• Go: Follows godoc best practices with comprehensive package comments
• TypeScript: Follows JSDoc standards with @component, @param, @returns tags
• Consistent with existing well-documented files (security.go, csrf.go, etc.)

This brings the codebase documentation coverage to production-ready standards, making it significantly easier for developers to understand, maintain, and extend the StreamSpace platform.