feat: implement project launch script run.sh and update README

specs/003-project-launch-script/quickstart.md

@@ -0,0 +1,39 @@
+# Quickstart: Project Launch Script
+
+## Prerequisites
+
+- Linux/macOS environment
+- Python 3.9+
+- Node.js 18+
+
+## Installation
+
+No installation required. The script is part of the repository.
+
+## Usage
+
+1.  Navigate to the project root:
+    ```bash
+    cd ss-tools
+    ```
+
+2.  Make the script executable (if not already):
+    ```bash
+    chmod +x run.sh
+    ```
+
+3.  Run the script:
+    ```bash
+    ./run.sh
+    ```
+
+## What it does
+
+1.  Checks for `python3` and `npm`.
+2.  Sets up a Python virtual environment in `backend/.venv` if it doesn't exist.
+3.  Installs backend dependencies from `backend/requirements.txt`.
+4.  Installs frontend dependencies if `frontend/node_modules` is missing.
+5.  Starts the backend server on port 8000.
+6.  Starts the frontend server on port 5173.
+7.  Streams logs from both services to the terminal.
+8.  Gracefully stops both services when you press `Ctrl+C`.