Implement Action Stage and Processor

[Haydart]

Task 007: Implement Action Stage and Processor

Description

Create TrendActionStage that assembles TrendAction from ProcessingContext, and TrendDetectionProcessor that orchestrates the 4-stage pipeline.

Acceptance Criteria

• Create TrendActionStage in src/domain/processor/stages/
• Extract memecoin_entry, matched_trend_id, new_trend_response, classification_reasoning from context
• Validate data completeness (memecoin_entry must exist)
• Validate either matched_trend_id OR new_trend_response exists
• Create TrendAction object (NO database writes)
• Store action in context.results["final_action"]
• Create TrendDetectionProcessor in src/domain/processor/
• Extend BaseStageProcessor
• Define 4-stage StageGraph: Metadata → Classification → Creation (conditional) → Action
• Implement handle early termination on errors
• Extract TrendAction from completed context

Technical Details

• TrendActionStage Location: src/domain/processor/stages/trend_action_stage.py
• TrendDetectionProcessor Location: src/domain/processor/trend_detection_processor.py
• Stage Order: TrendMetadataExtractionStage → TrendClassificationStage → NewTrendCreationStage → TrendActionStage
• ProcessingContext Results: memecoin_entry, matched_trend_id, new_trend_response, classification_reasoning, final_action
• Important: NO side effects in TrendActionStage (only data assembly)
• Output: Processor returns TrendAction for executor

Effort Estimate

• Size: M
• Hours: 6-8
• Parallel: false (depends on all stage tasks)