Implement scheduler history repository layer

[HyeockJinKim]

Story Description

Implement repository layer for managing scheduler history data access and manipulation.

Acceptance Criteria

• Create SchedulerHistoryRepository class in src/ai/backend/manager/repositories/scheduler/
• Implement methods for creating history records
• Implement methods for updating history status
• Support batch operations for sub-phase results
• Implement query methods for retrieving history
• Add proper error handling and logging
• Write comprehensive unit tests

Required Repository Methods

Core Operations

async def create_scheduler_history(
    session_id: SessionId,
    scheduling_step: SchedulingStep,
    message: str
) -> SchedulerHistoryId

async def update_scheduler_history_status(
    history_id: SchedulerHistoryId,
    status: HistoryStatus,
    error_code: Optional[str],
    message: str
) -> None

async def add_phase_results(
    history_id: SchedulerHistoryId,
    phase_results: list[PhaseResult]
) -> None

async def increment_retry_count(
    history_id: SchedulerHistoryId
) -> int

Query Operations

async def get_session_history(
    session_id: SessionId
) -> list[SchedulerHistory]

async def get_latest_history(
    session_id: SessionId,
    scheduling_step: SchedulingStep
) -> Optional[SchedulerHistory]

async def get_failed_histories(
    time_range: TimeRange
) -> list[SchedulerHistory]

Testing Requirements

• Unit tests for all repository methods
• Integration tests with database
• Performance tests for batch operations

JIRA Issue: BA-2440