Add Canva integration: Implement OAuth flow, token management, and asset export functionality

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Restore changes from lost commit (excluding creativity_examples binaries for HF)

Refactor ad creative generation and analysis: Updated the analyze_product and generate_ad_creatives functions to accept target audience segments for tailored analysis and creative generation. Enhanced the frontend to include a multi-select dropdown for target audiences, improving user experience. Adjusted styles for the new dropdown component and ensured proper handling of product image URLs for better ad results.

Amalfa updates: logo, favicon cursor, ref images deleted after use, gallery/lightbox; ignore reference_uploads

Add environment variable checks and logging on startup; update retry logic for image generation

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first commit