Data Model: Refactor CLI Scripts to Web Application

1. Connection Configuration

To support the "Dataset Mapper" tool with reusable connections (as per spec), we need a way to store external database credentials.

Table: connection_configs
Purpose: Stores credentials for external databases (e.g., PostgreSQL) used for column mapping.

Field	Type	Required	Description
`id`	UUID	Yes	Primary Key
`name`	String	Yes	User-friendly name (e.g., "Production DWH")
`type`	String	Yes	Enum: `postgres`, `excel` (future)
`host`	String	No	DB Host (for postgres)
`port`	Integer	No	DB Port (for postgres)
`database`	String	No	DB Name (for postgres)
`username`	String	No	DB User (for postgres)
`password`	String	No	Encrypted/Obfuscated password (for postgres)
`created_at`	DateTime	Yes	Creation timestamp
`updated_at`	DateTime	Yes	Last update timestamp

These models define the API contracts for the new tools.

class SearchRequest(BaseModel):
    env: str  # e.g., "dev", "prod"
    query: str # Regex pattern

class SearchResultItem(BaseModel):
    dataset_id: int
    dataset_name: str
    field: str
    match_context: str
    full_value: str

class SearchResponse(BaseModel):
    results: List[SearchResultItem]
    count: int

class DebugDbRequest(BaseModel):
    source_env: str
    target_env: str

class DebugDbResponse(BaseModel):
    source_db_count: int
    target_db_count: int
    details: Dict[str, Any] # Full JSON dump

class DatasetStructureRequest(BaseModel):
    env: str
    dataset_id: int