Initial commit: scheduler service extraction from portainer-core

Extracted standalone scheduler service with:
- FastAPI REST API for task management
- APScheduler-based task execution
- PostgreSQL persistence
- Docker container support
- Gitea Actions CI/CD workflow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/config.py

@@ -0,0 +1,73 @@
+"""
+Configuration management for The Scheduler.
+Uses Pydantic BaseSettings for type-safe environment variable loading.
+"""
+from functools import lru_cache
+from pydantic_settings import BaseSettings
+from pydantic import Field
+
+
+class Settings(BaseSettings):
+    """Application settings loaded from environment variables."""
+
+    # Application
+    app_name: str = Field(default="The Scheduler", alias="APP_NAME")
+    app_version: str = Field(default="1.0.0", alias="APP_VERSION")
+    debug: bool = Field(default=False, alias="DEBUG")
+    host: str = Field(default="0.0.0.0", alias="HOST")
+    port: int = Field(default=8090, alias="PORT")
+    log_level: str = Field(default="INFO", alias="LOG_LEVEL")
+
+    # Security
+    scheduler_api_key: str = Field(default="dev-key-change-me", alias="SCHEDULER_API_KEY")
+
+    # PostgreSQL
+    postgres_host: str = Field(default="postgres-shared", alias="POSTGRES_HOST")
+    postgres_port: int = Field(default=5432, alias="POSTGRES_PORT")
+    postgres_db: str = Field(default="library_scheduler", alias="POSTGRES_DB")
+    postgres_user: str = Field(default="library_scheduler_user", alias="POSTGRES_USER")
+    postgres_password: str = Field(default="", alias="POSTGRES_PASSWORD")
+
+    # Redis
+    redis_host: str = Field(default="redis-shared", alias="REDIS_HOST")
+    redis_port: int = Field(default=6379, alias="REDIS_PORT")
+    redis_db: int = Field(default=3, alias="REDIS_DB")
+
+    # Gitea
+    gitea_url: str = Field(default="http://gitea:3000", alias="GITEA_URL")
+    gitea_user: str = Field(default="library", alias="GITEA_USER")
+    gitea_password: str = Field(default="", alias="GITEA_PASSWORD")
+    gitea_ssh_host: str = Field(default="gitea", alias="GITEA_SSH_HOST")
+    gitea_ssh_port: int = Field(default=22, alias="GITEA_SSH_PORT")
+
+    # Backup Configuration
+    backup_retention_daily: int = Field(default=7, alias="BACKUP_RETENTION_DAILY")
+    backup_retention_weekly: int = Field(default=4, alias="BACKUP_RETENTION_WEEKLY")
+    backup_retention_monthly: int = Field(default=12, alias="BACKUP_RETENTION_MONTHLY")
+
+    # Documentation Mirroring
+    docs_mirror_path: str = Field(default="/docs-mirror", alias="DOCS_MIRROR_PATH")
+    docs_check_interval: int = Field(default=21600, alias="DOCS_CHECK_INTERVAL")  # 6 hours
+
+    @property
+    def database_url(self) -> str:
+        """PostgreSQL connection URL for APScheduler."""
+        return f"postgresql://{self.postgres_user}:{self.postgres_password}@{self.postgres_host}:{self.postgres_port}/{self.postgres_db}"
+
+    @property
+    def redis_url(self) -> str:
+        """Redis connection URL."""
+        return f"redis://{self.redis_host}:{self.redis_port}/{self.redis_db}"
+
+    class Config:
+        env_file = ".env"
+        case_sensitive = False
+
+
+@lru_cache
+def get_settings() -> Settings:
+    """
+    Get cached settings instance.
+    Using lru_cache ensures we only create one Settings instance.
+    """
+    return Settings()