Add start.sh to launch all three backends in one command

Starts pgvector (8000), Oracle 26ai (8001), and Oracle in-DB (8002)
backends concurrently and stops all on Ctrl+C.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

start.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+set -e
+
+BASE="$(cd "$(dirname "$0")" && pwd)"
+
+echo "Starting pgvector backend (port 8000)..."
+cd "$BASE/pgvector-demo/backend"
+uvicorn main:app --host 0.0.0.0 --port 8000 &
+PID1=$!
+
+echo "Starting Oracle 26ai backend (port 8001)..."
+cd "$BASE/oravector-demo/backend"
+uvicorn main_oracle:app --host 0.0.0.0 --port 8001 &
+PID2=$!
+
+echo "Starting Oracle in-DB backend (port 8002)..."
+cd "$BASE/oravector-demo/backend"
+uvicorn main_oracle_indb:app --host 0.0.0.0 --port 8002 &
+PID3=$!
+
+echo ""
+echo "All backends running:"
+echo "  http://localhost:8000/ui/  — pgvector"
+echo "  http://localhost:8001/ui/  — Oracle 26ai"
+echo "  http://localhost:8002/ui/  — Oracle In-DB"
+echo ""
+echo "Press Ctrl+C to stop all."
+
+trap "kill $PID1 $PID2 $PID3 2>/dev/null; echo 'Stopped.'" EXIT
+wait