fix: centralize AI model constants and fix invalid model names

[hotyoyo]

Summary

This PR centralizes all AI model configurations into a single file and fixes critical bugs where invalid model names were being used.

Problem

The codebase had several issues:

1. Invalid model names: gpt-5-mini and gpt-5.2 do not exist and would cause API failures
2. Scattered model configurations: Model names were hardcoded across 8+ files, making updates difficult
3. No single source of truth: Changes required modifying multiple files

Solution

Created src/lib/models.ts with:

• CHAT_MODELS - Chat completion models (GPT-4o, GPT-4o-mini)
• EMBEDDING_MODELS - Text embedding models (Ada-002)
• TRANSCRIPTION_MODELS - Audio transcription models
• DEFAULT_MODELS - Preset configurations for common use cases
• TypeScript types for type safety

Changes

File	Change
src/lib/models.ts	New centralized model configuration
src/app/api/AIAssistant/services/webSearchAgent.ts	Fix gpt-5-mini → gpt-4o-mini
src/app/api/AIAssistant/route.ts	Fix gpt-5.2 → gpt-4o
src/app/api/predictive-document-analysis/services/analysisEngine.ts	Fix gpt-5.2 → gpt-4o
src/app/api/predictive-document-analysis/services/referenceExtractor.ts	Fix gpt-5.2 → gpt-4o
src/app/api/predictive-document-analysis/utils/embeddings.ts	Use centralized constants
src/app/api/uploadDocument/route.ts	Use centralized constants
src/app/api/study-agent/chat/route.ts	Use centralized constants
src/app/api/study-agent/speech-to-text/route.ts	Use centralized constants

Usage Example

import { DEFAULT_MODELS, CHAT_MODELS } from "~/lib/models";

// Use default presets
const chat = new ChatOpenAI({
  modelName: DEFAULT_MODELS.ANALYSIS, // gpt-4o
});

// Or specific models
const embeddings = new OpenAIEmbeddings({
  model: DEFAULT_MODELS.EMBEDDING, // text-embedding-ada-002
});

Benefits

• Bug fix: Prevents API failures from invalid model names
• Maintainability: Single place to update model versions
• Type safety: TypeScript types for model selections
• Documentation: Clear descriptions of each model"s use case

Breaking Changes

None - This is a refactor with bug fixes. All existing functionality is preserved.

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Project	Deployment	Review	Updated (UTC)
pdr-ai-v2	Ready	Preview, Comment	Dec 19, 2025 7:28pm

[Deodat-Lawson]

Good idea. I still want to keep everything updated to be using GPT 5