fix: 统一数据库默认密码 change_me → cyrene_pass

Docker Compose 和 .env 使用 cyrene_pass，但 5 个 Go 源码文件
和 DevTools config.js 中的 fallback 密码仍是 change_me，
导致 memory-service/tool-engine/gateway 启动后 DB 认证失败。
修复 7 个文件中的硬编码 fallback 密码，统一为 cyrene_pass。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/.env.example

@@ -6,7 +6,7 @@ LOG_LEVEL=debug
 POSTGRES_HOST=localhost
 POSTGRES_PORT=5432
 POSTGRES_USER=cyrene
-POSTGRES_PASSWORD=change_me
+POSTGRES_PASSWORD=cyrene_pass
 POSTGRES_DB=cyrene_ai
 
 # ========== Redis ==========

backend/ai-core/cmd/main.go

@@ -249,7 +249,7 @@ func buildDatabaseURL() string {
 	host := getEnv("POSTGRES_HOST", "localhost")
 	port := getEnv("POSTGRES_PORT", "5432")
 	user := getEnv("POSTGRES_USER", "cyrene")
-	password := getEnv("POSTGRES_PASSWORD", "change_me")
+	password := getEnv("POSTGRES_PASSWORD", "cyrene_pass")
 	dbname := getEnv("POSTGRES_DB", "cyrene_ai")
 	sslmode := getEnv("POSTGRES_SSLMODE", "disable")
 

backend/gateway/internal/config/config.go

@@ -103,7 +103,7 @@ func Load() *Config {
 		PostgresHost: getEnv("POSTGRES_HOST", "localhost"),
 		PostgresPort: getEnv("POSTGRES_PORT", "5432"),
 		PostgresUser: getEnv("POSTGRES_USER", "cyrene"),
-		PostgresPass: getEnv("POSTGRES_PASSWORD", "change_me"),
+		PostgresPass: getEnv("POSTGRES_PASSWORD", "cyrene_pass"),
 		PostgresDB:   getEnv("POSTGRES_DB", "cyrene_ai"),
 
 		RedisHost: getEnv("REDIS_HOST", "localhost"),

backend/memory-service/internal/config/config.go

@@ -29,7 +29,7 @@ func buildDatabaseURL() string {
 	host := getEnv("POSTGRES_HOST", "localhost")
 	port := getEnv("POSTGRES_PORT", "5432")
 	user := getEnv("POSTGRES_USER", "cyrene")
-	password := getEnv("POSTGRES_PASSWORD", "change_me")
+	password := getEnv("POSTGRES_PASSWORD", "cyrene_pass")
 	dbname := getEnv("POSTGRES_DB", "cyrene_ai")
 	sslmode := getEnv("POSTGRES_SSLMODE", "disable")
 

backend/tool-engine/internal/store/call_log_store.go

@@ -274,7 +274,7 @@ func DBUrlFromEnv() string {
 	host := getEnv("DB_HOST", "localhost")
 	port := getEnv("DB_PORT", "5432")
 	user := getEnv("DB_USER", "cyrene")
-	pass := getEnv("DB_PASSWORD", "change_me")
+	pass := getEnv("DB_PASSWORD", "cyrene_pass")
 	dbname := getEnv("DB_NAME", "cyrene_ai")
 	sslmode := getEnv("DB_SSLMODE", "disable")