chore: initialize git flow, ci pipeline, and changelog

.github/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: Sencho CI
+
+on:
+  pull_request:
+    branches: [ main, develop ]
+  push:
+    branches: [ develop ]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install Backend Dependencies
+        working-directory: ./backend
+        run: npm ci
+
+      - name: Build Backend (TypeScript)
+        working-directory: ./backend
+        run: npm run build
+
+      - name: Install Frontend Dependencies
+        working-directory: ./frontend
+        run: npm ci
+
+      - name: Build Frontend (Vite/React)
+        working-directory: ./frontend
+        run: npm run build

CHANGELOG.md

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+# Changelog
+
+All notable changes to this project will be documented in this file.
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+### Added
+- Git Flow branching strategy and branch protection.
+- GitHub Actions CI pipeline for automated TypeScript build verification.