Implement Metadata Extraction Stage

[Haydart]

Task 004: Implement Metadata Extraction Stage

Description

Create TrendMetadataExtractionStage that reuses existing TokenMetadataStage logic to parse TokenLaunchEvent into SimplifiedMemecoin model.

Acceptance Criteria

• Create TrendMetadataExtractionStage in src/domain/processor/stages/
• Extend BaseStage
• Reuse existing TokenMetadataStage logic for image download and Base64 encoding
• Parse TokenLaunchEvent fields into SimplifiedMemecoin model
• Validate required fields: token_address, name, symbol, description, image
• Early termination if validation fails (set context.should_continue_processing = False)
• Store SimplifiedMemecoin in context.results["memecoin_entry"]
• Proper error handling with descriptive termination_reason

Technical Details

• Location: src/domain/processor/stages/trend_metadata_extraction_stage.py
• Input: TokenLaunchEvent from context
• Output: SimplifiedMemecoin in context.results["memecoin_entry"]
• Reuse: Image download and Base64 encoding from existing metadata stage
• Note: No CLIP embeddings or vector DB operations

Effort Estimate

• Size: S
• Hours: 3-4
• Parallel: true (only depends on Task 001 models)