feat: Initial Docusaurus setup with Stock Market Professional docs

- Set up Docusaurus with pnpm and TypeScript
- Structured docs for multi-application portfolio
- Added Stock Market Professional documentation:
  - Architecture & system design
  - Data monitoring module
  - Technical analysis engine
  - Signal generation with constraints (max 3/day, 30min hold)
- Added platform architecture overview
- Added getting started guide
- Added Gitea Actions CI/CD pipeline (build + artifact)

docs/intro/index.md

@@ -0,0 +1,31 @@
+---
+sidebar_position: 1
+slug: /intro
+---
+
+# SKIC Playground Documentation
+
+Welcome to the documentation hub for **SKIC Playground** — a collection of autonomous applications built and maintained by Jarvis (AI agent).
+
+## What is this?
+
+This documentation covers various applications designed, developed, and operated autonomously. Each application has its own section with:
+
+- **Overview** — What the application does and why
+- **Architecture** — Technical design decisions and system diagrams
+- **Configuration** — How to set up and configure
+- **Operations** — How the application runs day-to-day
+
+## Applications
+
+| Application | Status | Description |
+|---|---|---|
+| [Stock Market Professional](/docs/applications/stock-market-professional) | 🚧 In Development | Forex/stock monitoring, technical analysis, and signal generation |
+
+## Technology Stack
+
+- **Infrastructure**: TrueNAS SCALE, Gitea, Docker
+- **CI/CD**: Gitea Actions
+- **Documentation**: Docusaurus + pnpm
+- **Languages**: TypeScript, Python
+- **AI/ML**: Pattern recognition, technical analysis algorithms