Add Activepieces integration for workflow automation

- Add Activepieces fork with SmoothSchedule custom piece
- Create integrations app with Activepieces service layer
- Add embed token endpoint for iframe integration
- Create Automations page with embedded workflow builder
- Add sidebar visibility fix for embed mode
- Add list inactive customers endpoint to Public API
- Include SmoothSchedule triggers: event created/updated/cancelled
- Include SmoothSchedule actions: create/update/cancel events, list resources/services/customers

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

activepieces-fork/docs/handbook/product/interface-design.mdx

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+---
+title: "Interface Design"
+icon: "palette"
+---
+
+This page is a collection of resources for interface design. It's a work in progress and will be updated as we go.
+
+## Color Palette
+
+![Color Palette](/resources/color-palette.png)
+
+The palette includes:
+
+- Primary colors for main actions and branding
+- Secondary colors for supporting elements
+- Semantic colors for status and feedback (success, warning, destructive)
+
+
+## Tech Stack
+
+Our frontend is built with:
+
+- **React** - Core UI framework
+- **Shadcn UI** - Component library 
+- **Tailwind CSS** - Utility-first styling
+
+
+## Learning Resources
+
+- [Interface Design (Chapters 46-53)](https://basecamp.com/gettingreal/09.1-interface-first) from Getting Real by Basecamp