fix(api): History rewriting should delete the current message.

fix(UI): Model changes shouldn't submit the form.

.github/copilot-instructions.md

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+# GitHub Copilot Instructions for Perplexica
+
+This file provides context and guidance for GitHub Copilot when working with the Perplexica codebase.
+
+## Project Overview
+
+Perplexica is an open-source AI-powered search engine that uses advanced machine learning to provide intelligent search results. It combines web search capabilities with LLM-based processing to understand and answer user questions, similar to Perplexity AI but fully open source.
+
+## Key Components
+
+- **Frontend**: Next.js application with React components (in `/src/components` and `/src/app`)
+- **Backend Logic**: Node.js backend with API routes (in `/src/app/api`) and library code (in `/src/lib`)
+- **Search Engine**: Uses SearXNG as a metadata search engine
+- **LLM Integration**: Supports multiple models including OpenAI, Anthropic, Groq, Ollama (local models)
+- **Database**: SQLite database managed with Drizzle ORM
+
+## Architecture
+
+The system works through these main steps:
+
+- User submits a query
+- The system determines if web search is needed
+- If needed, it searches the web using SearXNG
+- Results are ranked using embedding-based similarity search
+- LLMs are used to generate a comprehensive response with cited sources
+
+## Key Technologies
+
+- **Frontend**: React, Next.js, Tailwind CSS
+- **Backend**: Node.js
+- **Database**: SQLite with Drizzle ORM
+- **AI/ML**: LangChain for orchestration, various LLM providers
+- **Search**: SearXNG integration
+- **Embedding Models**: For re-ranking search results
+
+## Project Structure
+
+- `/src/app`: Next.js app directory with page components and API routes
+- `/src/components`: Reusable UI components
+- `/src/lib`: Backend functionality
+  - `/lib/search`: Search functionality and meta search agent
+  - `/lib/db`: Database schema and operations
+  - `/lib/providers`: LLM and embedding model integrations
+  - `/lib/prompts`: Prompt templates for LLMs
+  - `/lib/chains`: LangChain chains for various operations
+
+## Focus Modes
+
+Perplexica supports multiple specialized search modes:
+
+- All Mode: General web search
+- Local Research Mode: Research and interact with local files with citations
+- Chat Mode: Have a creative conversation
+- Academic Search Mode: For academic research
+- YouTube Search Mode: For video content
+- Wolfram Alpha Search Mode: For calculations and data analysis
+- Reddit Search Mode: For community discussions
+
+## Development Workflow
+
+- Use `npm run dev` for local development
+- Format code with `npm run format:write` before committing
+- Database migrations: `npm run db:push`
+- Build for production: `npm run build`
+- Start production server: `npm run start`
+
+## Configuration
+
+The application uses a `config.toml` file (created from `sample.config.toml`) for configuration, including:
+
+- API keys for various LLM providers
+- Database settings
+- Search engine configuration
+- Similarity measure settings
+
+## Common Tasks
+
+When working on this codebase, you might need to:
+
+- Add new API endpoints in `/src/app/api`
+- Modify UI components in `/src/components`
+- Extend search functionality in `/src/lib/search`
+- Add new LLM providers in `/src/lib/providers`
+- Update database schema in `/src/lib/db/schema.ts`
+- Create new prompt templates in `/src/lib/prompts`
+- Build new chains in `/src/lib/chains`
+
+## AI Behavior
+
+- Avoid conciliatory language
+- It is not necessary to apologize
+- If you don't know the answer, ask for clarification
+- Do not add additional packages or dependencies unless explicitly requested
+- Only make changes to the code that are relevant to the task at hand