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/build-pieces/building-pieces/overview.mdx

@@ -0,0 +1,31 @@
+---
+title: 'Overview'
+description: 'This section helps developers build and contribute pieces.'
+icon: 'hand-wave'
+---
+
+Building pieces is fun and important; it allows you to customize Activepieces for your own needs.
+
+<Tip>
+ We love contributions! In fact, most of the pieces are contributed by the community. Feel free to open a pull request.
+</Tip>
+<Tip>
+**Friendly Tip:**
+For the fastest support, we recommend joining our Discord community. We are dedicated to addressing every question and concern raised there.
+</Tip>
+
+
+<CardGroup cols={2}>
+  <Card title="Code with TypeScript" icon="code">
+    Build pieces using TypeScript for a more powerful and flexible development process.
+  </Card>
+  <Card title="Hot Reloading" icon="cloud-bolt">
+    See your changes in the browser within 7 seconds.
+  </Card>
+  <Card title="Open Source" icon="earth-americas">
+    Work within the open-source environment, explore, and contribute to other pieces.
+  </Card>
+  <Card title="Community Support" icon="people">
+    Join our large community, where you can ask questions, share ideas, and develop alongside others.
+  </Card>
+</CardGroup>