feat: refactor database connection handling and add legacy map loading functionality

- Updated check-connections.mts to use Prisma with PostgreSQL adapter.
- Introduced databaseUrl.ts for resolving database URLs from environment variables.
- Added legacyMapLoader.ts to load and parse legacy map data.
- Implemented scenarioSeeder.ts to seed scenario data into the database.
- Created tests for scenario seeding in scenarioSeeder.test.ts.
- Configured Prisma datasource in prisma.config.ts to support dynamic database URLs.

app/game-engine/src/scenario/databaseUrl.ts

@@ -0,0 +1,70 @@
+import fs from 'node:fs/promises';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const DEFAULT_ENV_FILE = path.resolve(__dirname, '..', '..', '..', '..', '.env.ci');
+
+type EnvMap = Record<string, string | undefined>;
+
+export interface DatabaseUrlOptions {
+    envFile?: string;
+    env?: NodeJS.ProcessEnv;
+}
+
+const parseEnvFile = (rawText: string): EnvMap => {
+    const env: EnvMap = {};
+    const lines = rawText.split(/\r?\n/);
+    for (const line of lines) {
+        const trimmed = line.trim();
+        if (!trimmed || trimmed.startsWith('#')) {
+            continue;
+        }
+        const index = trimmed.indexOf('=');
+        if (index < 0) {
+            continue;
+        }
+        const key = trimmed.slice(0, index).trim();
+        let value = trimmed.slice(index + 1).trim();
+        if (
+            (value.startsWith('"') && value.endsWith('"')) ||
+            (value.startsWith("'") && value.endsWith("'"))
+        ) {
+            value = value.slice(1, -1);
+        }
+        env[key] = value;
+    }
+    return env;
+};
+
+const loadEnvFile = async (envFile: string): Promise<EnvMap> => {
+    try {
+        const text = await fs.readFile(envFile, 'utf8');
+        return parseEnvFile(text);
+    } catch {
+        return {};
+    }
+};
+
+export const resolveDatabaseUrl = async (
+    options?: DatabaseUrlOptions
+): Promise<string> => {
+    const env = options?.env ?? process.env;
+    if (env.DATABASE_URL) {
+        return env.DATABASE_URL;
+    }
+
+    const envFile = options?.envFile ?? DEFAULT_ENV_FILE;
+    const fileEnv = await loadEnvFile(envFile);
+    if (fileEnv.DATABASE_URL) {
+        return fileEnv.DATABASE_URL;
+    }
+
+    const host = env.POSTGRES_HOST ?? fileEnv.POSTGRES_HOST ?? '127.0.0.1';
+    const port = env.POSTGRES_PORT ?? fileEnv.POSTGRES_PORT ?? '15432';
+    const user = env.POSTGRES_USER ?? fileEnv.POSTGRES_USER ?? 'sammo';
+    const password = env.POSTGRES_PASSWORD ?? fileEnv.POSTGRES_PASSWORD ?? '';
+    const dbName = env.POSTGRES_DB ?? fileEnv.POSTGRES_DB ?? 'sammo';
+    return `postgresql://${user}:${password}@${host}:${port}/${dbName}?schema=public`;
+};