Refactor README and scripts for Lagged Oil-Unemployment Chart

Update README.md to reflect new project focus on lagged oil and unemployment charting. Revise installation instructions, quickstart guide, and repository structure. Modify scripts for data fetching and plotting, and add a new SQLite database for storing FRED data. Introduce a startup script to streamline setup and execution.

startup.sh

@@ -1,9 +1,61 @@
 #!/usr/bin/env bash
+# -------------------------------------------------------------------
+# startup.sh  — prepare Python env, ensure dependencies, FRED data,
+#              and run a command inside the venv
+# Usage:
+#   ./startup.sh [command…]
+# Automatically:
+#  - Upgrades pip & setuptools (ensuring distutils on Python 3.12+)
+#  - Creates venv if missing
+#  - Installs requirements
+#  - Downloads data/fred.db if missing
+# -------------------------------------------------------------------
 set -euo pipefail
 
-python3 -m venv venv
-source venv/bin/activate
+VENV_DIR="venv"
+REQ_FILE="requirements.txt"
+WHEELHOUSE="wheelhouse"
+DATA_DB="data/fred.db"
 
-pip install --no-index --find-links=wheelhouse -r requirements.txt
+# 1) Create or reuse venv
+if [[ ! -d "$VENV_DIR" ]]; then
+  echo "🔧 Creating virtual-env…"
+  python3 -m venv "$VENV_DIR"
+fi
+# Activate
+# shellcheck disable=SC1090
+source "$VENV_DIR/bin/activate"
 
-echo "✅  Virtual-env ready (offline install)."
+# 2) Upgrade pip & setuptools (to provide distutils on Py3.12+)
+echo "🛠 Upgrading pip & setuptools…"
+pip install --upgrade pip setuptools
+
+# 3) Install project dependencies
+PIP_OPTS=(install --upgrade --no-input)
+if [[ -d "$WHEELHOUSE" ]]; then
+  echo "📦 Installing from wheelhouse…"
+  pip "${PIP_OPTS[@]}" --no-index --find-links="$WHEELHOUSE" -r "$REQ_FILE" \
+    || { echo "⚠️ Wheelhouse failed—falling back to PyPI…"; \
+         pip "${PIP_OPTS[@]}" -r "$REQ_FILE"; }
+else
+  echo "🌐 Installing from PyPI…"
+  pip "${PIP_OPTS[@]}" -r "$REQ_FILE"
+fi
+
+echo "✅ Virtual-env ready ($(python -V))"
+
+# 4) Ensure data/fred.db exists
+if [[ ! -f "$DATA_DB" ]]; then
+  echo "🔄 $DATA_DB not found—downloading FRED series…"
+  python scripts/refresh_data.py
+fi
+
+# 5) Decide what to run
+if [[ $# -gt 0 ]]; then
+  CMD=("$@")
+else
+  CMD=(python scripts/lagged_oil_unrate_chart_styled.py --offset 18)
+fi
+
+echo "🚀 Executing: ${CMD[*]}"
+exec "${CMD[@]}"