chore(demo-urls): backfill 18 recipes with vendor demo URLs

[sazed-bot]

Summary

• Backfills demo_url on 18 recipes using deterministic vendor patterns
• Leaves Custom-framework recipes null where there is no confident vendor-demo URL

Populated

• conversational-article-discussion-assistant: https://github.com/cartesia-ai/dev-showcase/tree/main/studypal
• customer-support-agent-with-ticket-status-lookup: https://github.com/HumeAI/hume-api-examples/tree/main/evi/evi-python-phone-calling-proxy-server
• desktop-robot-assistant-with-voice-controlled-manipulation: https://github.com/livekit-examples/embodied-ai-hackathon
• doctor-appointment-scheduler-with-intake-form: https://github.com/cartesia-ai/line/tree/main/examples/form_filler
• five-minute-inbound-lead-qualification-and-transfer: https://github.com/Bland-AI/Bland-AI-Cookbooks/tree/main/inbound-lead-qualification
• hotel-front-desk-receptionist: https://github.com/dlange-aai/hotel-booking-agent
• langchain-agent-voice-demo-with-vocode-core: https://github.com/vocodedev/vocode-core/tree/main/apps/langchain_agent
• medical-office-receptionist-for-appointment-booking-and-triage: https://github.com/RaheesAhmed/MediVoice-AI
• multi-agent-voice-ai-workflow-with-python: https://github.com/livekit-examples/multi-agent-python
• multi-intent-call-router-with-rag-instructions: https://dashboard.vapi.ai/import?id=multi_intent_handler
• real-time-speech-transcription-frontend: https://github.com/livekit-examples/transcription-frontend-groq
• real-time-voice-agent-with-neural-turn-detection: https://github.com/kelsey-aai/voice-agent-livekit-universal-3-pro
• saas-customer-support-agent-with-assemblyai: https://github.com/sampleapp-ai/assemblyai-voice-agent-pipecat
• sales-representative-with-lead-extraction-and-company-research: https://github.com/cartesia-ai/line/tree/main/examples/sales_with_leads
• sms-one-time-password-verification-for-identity-confirmation: https://dashboard.vapi.ai/import?id=otp-sms
• travel-companion-with-location-based-recommendations: https://github.com/pipecat-ai/pipecat-examples/tree/main/travel-companion
• voicemail-detection-assistant-for-outbound-calls: https://dashboard.vapi.ai/import?id=voicemail_detection
• weather-information-assistant-with-function-calling: https://github.com/daily-co/pcc-groq-llama

Left null with reason

• customer-service-agent-with-function-calling-and-order-management: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• customer-support-and-appointment-booking-assistant: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• dental-office-appointment-scheduling-agent: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• ecommerce-refund-processing-assistant: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• flowise-ai-voice-agent-with-twilio-conversationrelay: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• inbound-phone-order-status-agent: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• insurance-lead-follow-up-agent: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• medical-assistant-for-clinical-note-taking: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• outbound-sales-assistant-for-airpods: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• phone-based-voice-agent-with-web-search: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• pizza-ordering-voice-agent: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• smart-city-voice-ai-demo-for-harbour-city-operations: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• telephony-voice-agent-with-inbound-and-outbound-call-handling: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null
• two-way-conversational-speech-assistant: Custom framework, no deterministic vendor demo rule; false demo URLs are worse than null

Tests

• npm run validate (fails on 3 pre-existing title/vendor-name errors unrelated to demo_url: flowise-ai-voice-agent-with-twilio-conversationrelay, langchain-agent-voice-demo-with-vocode-core, saas-customer-support-agent-with-assemblyai)