feat: add fullstack TypeScript template with Docker support

- Created package.json for managing workspaces (frontend and backend)
- Added scripts for development, build, testing, and Docker operations
- Implemented kill-dev-processes.sh script to terminate development processes gracefully

.devcontainer/Dockerfile

@@ -0,0 +1,25 @@
+FROM node:18
+
+# Install git and other useful tools
+RUN apt-get update && apt-get install -y \
+    git \
+    curl \
+    vim \
+    && rm -rf /var/lib/apt/lists/*
+
+# Set working directory
+WORKDIR /workspace
+
+# Install global packages
+RUN npm install -g typescript ts-node nodemon
+
+# Create user with same UID as host (for file permissions)
+ARG USERNAME=node
+ARG USER_UID=1000
+ARG USER_GID=$USER_UID
+
+RUN groupmod --gid $USER_GID $USERNAME \
+    && usermod --uid $USER_UID --gid $USER_GID $USERNAME \
+    && chown -R $USER_UID:$USER_GID /home/$USERNAME
+
+USER $USERNAME