Refactor supervisor to use environment variables and simplify binary

- Created scripts/generate_secret.sh to generate supervisor secrets
- Added .env.example with all configuration options
- Created scripts/environment.sh to load env vars from .env
- Updated scripts/run.sh to use env vars and pass as flags
- Simplified supervisor binary:
  - Removed bootstrap-admin-key and config file support
  - Made admin-secret required
  - Minimal output (only URLs)
  - Clean startup with no verbose logging
- Updated .gitignore for .env and log files

scripts/environment.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+# Load environment variables from .env file
+
+SCRIPT_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+PROJECT_DIR=$(cd "$SCRIPT_DIR/.." && pwd)
+ENV_FILE="$PROJECT_DIR/.env"
+
+if [ -f "$ENV_FILE" ]; then
+    # Export variables from .env file
+    set -a
+    source "$ENV_FILE"
+    set +a
+    echo "✅ Loaded environment from .env"
+else
+    echo "⚠️  No .env file found at $ENV_FILE"
+    echo "   Copy .env.example to .env and configure your settings"
+    exit 1
+fi