fix: Move devcontainer to repo root for Codespaces detection

GitHub Codespaces only looks for devcontainer.json in:
- .devcontainer/devcontainer.json
- .devcontainer/<subfolder>/devcontainer.json
- .devcontainer.json

It does NOT look inside project subfolders like autogpt_platform/.devcontainer/

Moved to .devcontainer/platform/ which:
1. Will be detected by Codespaces
2. Allows multiple configs (platform vs classic)
3. Updated all path references accordingly

.devcontainer/platform/scripts/postcreate.sh

@@ -0,0 +1,131 @@
+#!/bin/bash
+# =============================================================================
+# POSTCREATE SCRIPT - Runs after container creation
+# =============================================================================
+# This script runs once when a codespace is first created. It starts the
+# dependency services and prepares the environment for development.
+#
+# NOTE: Backend and Frontend run NATIVELY (not in Docker) to ensure you're
+# always running the current branch's code, not stale prebuild code.
+# =============================================================================
+
+set -e  # Exit on error
+
+echo "🚀 Setting up your development environment..."
+
+cd /workspaces/AutoGPT/autogpt_platform
+
+# =============================================================================
+# Ensure Docker is available
+# =============================================================================
+if [ -e /var/run/docker-host.sock ]; then
+    sudo ln -sf /var/run/docker-host.sock /var/run/docker.sock 2>/dev/null || true
+fi
+
+# Wait for Docker to be ready
+echo "⏳ Waiting for Docker..."
+timeout 60 bash -c 'until docker info &>/dev/null; do sleep 1; done'
+echo "✅ Docker is ready"
+
+# =============================================================================
+# Start Dependency Services ONLY
+# =============================================================================
+# We only start infrastructure deps in Docker.
+# Backend/Frontend run natively to use the current branch's code.
+# =============================================================================
+echo "🐳 Starting dependency services..."
+
+# Start core dependencies (DB, Auth, Redis, RabbitMQ)
+docker compose up -d db redis rabbitmq kong auth
+
+# Wait for PostgreSQL to be healthy
+echo "⏳ Waiting for PostgreSQL..."
+timeout 120 bash -c '
+until docker compose exec -T db pg_isready -U postgres &>/dev/null; do
+    sleep 2
+    echo "  Waiting for database..."
+done
+'
+echo "✅ PostgreSQL is ready"
+
+# Wait for Redis
+echo "⏳ Waiting for Redis..."
+timeout 60 bash -c 'until docker compose exec -T redis redis-cli ping &>/dev/null; do sleep 1; done'
+echo "✅ Redis is ready"
+
+# Wait for RabbitMQ
+echo "⏳ Waiting for RabbitMQ..."
+timeout 90 bash -c 'until docker compose exec -T rabbitmq rabbitmq-diagnostics -q ping &>/dev/null; do sleep 2; done'
+echo "✅ RabbitMQ is ready"
+
+# =============================================================================
+# Run Database Migrations
+# =============================================================================
+echo "🔄 Running database migrations..."
+
+cd backend
+
+# Ensure Poetry is in PATH
+export PATH="$HOME/.local/bin:$PATH"
+
+# Run migrations
+poetry run prisma migrate deploy
+poetry run prisma generate
+poetry run gen-prisma-stub || true
+
+cd ..
+
+# =============================================================================
+# Seed Test Data (Minimal)
+# =============================================================================
+echo "🌱 Checking test data..."
+
+cd backend
+
+# Check if test data already exists (idempotent)
+if poetry run python -c "
+import asyncio
+from backend.data.db import prisma
+
+async def check():
+    await prisma.connect()
+    count = await prisma.user.count()
+    await prisma.disconnect()
+    return count > 0
+
+print('exists' if asyncio.run(check()) else 'empty')
+" 2>/dev/null | grep -q "exists"; then
+    echo "  Test data already exists, skipping seed"
+else
+    echo "  Running E2E test data creator..."
+    poetry run python test/e2e_test_data.py || echo "⚠️ Test data seeding had issues (may be partial)"
+fi
+
+cd ..
+
+# =============================================================================
+# Print Welcome Message
+# =============================================================================
+echo ""
+echo "=============================================="
+echo "🎉 CODESPACE READY!"
+echo "=============================================="
+echo ""
+echo "📍 Services Running (Docker):"
+echo "   PostgreSQL:  localhost:5432"
+echo "   Redis:       localhost:6379"
+echo "   RabbitMQ:    localhost:5672 (mgmt: 15672)"
+echo "   Supabase:    localhost:8000"
+echo ""
+echo "🚀 Start Development:"
+echo "   make run-backend   # Start backend (localhost:8006)"
+echo "   make run-frontend  # Start frontend (localhost:3000)"
+echo ""
+echo "   Or run both in separate terminals!"
+echo ""
+echo "🔑 Test Account:"
+echo "   Email:    test123@gmail.com"
+echo "   Password: testpassword123"
+echo ""
+echo "📚 Full docs: .devcontainer/README.md"
+echo ""