Implement Trend Firebase Executor

[Haydart]

Task 008: Implement Trend Firebase Executor

Description

Create TrendFirebaseExecutor that handles all Firebase write operations with race condition prevention via transactions.

Acceptance Criteria

• Create TrendFirebaseExecutor in src/domain/executor/
• Extend BaseExecutor
• Implement execute(action: TrendAction) method with routing logic
• Implement _append_to_existing_trend(action) for matched_trend_id path
• Implement _create_new_trend_with_retry(action) for new trend path
• Call firebase_service.append_memecoin_to_trend() with atomic operations
• Call firebase_service.check_and_promote_trend() after successful append
• Call firebase_service.create_trend_with_retry() with max_retries=3
• Implement console output with _print_success() and _print_error()
• Proper error handling for Firebase write failures

Technical Details

• Location: src/domain/executor/trend_firebase_executor.py
• Execution flow: if action.matched_trend_id → append, else → create
• Append path: append_memecoin_to_trend → check_and_promote_trend → console output
• Create path: create_trend_with_retry (3 retries) → console output
• Transaction-based duplicate prevention handled in SimpleFirebaseService
• Console format: "Appended {token_name} to trend {trend_id[:8]}..." or "Created new trend: {trend_name}"

Effort Estimate

• Size: M
• Hours: 6-8
• Parallel: false (depends on Tasks 001, 002, 007)