chore: remove internal docs from repo, update public documentation

Remove docs/superpowers/, .claude/ config, and PRD.md from version
control (kept locally via .gitignore). Update README, CHANGELOG,
VitePress docs, and .env.example to reflect recent features: Files
page, teams, admin settings, persistent storage, and various API
improvements.

apps/docs/guide/architecture.md

@@ -47,11 +47,12 @@ Shared TypeScript types, constants (like `APP_VERSION` and tool definitions), an
 ### API (`apps/api`)
 
 A Fastify v5 server that handles:
-- File uploads and temporary workspace management
+- File uploads, temporary workspace management, and persistent file storage
 - Tool execution (routes each tool request to the image engine or AI bridge)
 - Pipeline orchestration (chaining multiple tools sequentially)
 - Batch processing with concurrency control via p-queue
-- User authentication, API key management, and rate limiting
+- User authentication, teams, API key management, and rate limiting
+- Admin settings (tool visibility, feature flags, cleanup config, branding)
 - Swagger/OpenAPI documentation at `/api/docs`
 - Serving the built frontend as a SPA in production
 
@@ -61,6 +62,8 @@ Key dependencies: Fastify, Drizzle ORM, better-sqlite3, Sharp, Zod for validatio
 
 A React 19 single-page app built with Vite. Uses Zustand for state management, Tailwind CSS v4 for styling, and Lucide for icons. Communicates with the API over REST and SSE (for progress tracking).
 
+Pages include a tool workspace, a Files page for managing persistent uploads and results, an automation/pipeline builder, and an admin settings panel.
+
 The built frontend gets served by the Fastify backend in production, so there is no separate web server in the Docker container.
 
 ### Docs (`apps/docs`)