chore: 更新 .gitignore 忽略配置文件并还原 Makefile

- 添加 backend/config.yaml 到 .gitignore（包含敏感信息）
- 添加 deploy/config.yaml 到 .gitignore（包含敏感信息）
- 添加 backend/.installed 到 .gitignore
- 还原 Makefile 到原始版本

backend/config.yaml

@@ -1,38 +0,0 @@
-server:
-  host: "0.0.0.0"
-  port: 8080
-  mode: "debug"  # debug/release
-
-database:
-  host: "127.0.0.1"
-  port: 5432
-  user: "postgres"
-  password: "XZeRr7nkjHWhm8fw"
-  dbname: "sub2api"
-  sslmode: "disable"
-
-redis:
-  host: "127.0.0.1"
-  port: 6379
-  password: ""
-  db: 0
-
-jwt:
-  secret: "your-secret-key-change-in-production"
-  expire_hour: 24
-
-default:
-  admin_email: "admin@sub2api.com"
-  admin_password: "admin123"
-  user_concurrency: 5
-  user_balance: 0
-  api_key_prefix: "sk-"
-  rate_multiplier: 1.0
-
-# Timezone configuration (similar to PHP's date_default_timezone_set)
-# This affects ALL time operations:
-# - Database timestamps
-# - Usage statistics "today" boundary
-# - Subscription expiry times
-# Common values: Asia/Shanghai, America/New_York, Europe/London, UTC
-timezone: "Asia/Shanghai"