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)

tsconfig.json

@@ -0,0 +1,12 @@
+// This file is not used by "docusaurus start/build" commands.
+// It is here to improve your IDE experience (type-checking, autocompletion...),
+// and can also run the package.json "typecheck" script manually.
+{
+  "extends": "@docusaurus/tsconfig",
+  "compilerOptions": {
+    "baseUrl": ".",
+    "ignoreDeprecations": "6.0",
+    "strict": true
+  },
+  "exclude": [".docusaurus", "build"]
+}