Added CLAUDE.md with project setup and architecture details (#589)

Author: SommerEngineering

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+MindWork AI Studio is a cross-platform desktop application for interacting with Large Language Models (LLMs). The app uses a hybrid architecture combining a Rust Tauri runtime (for the native desktop shell) with a .NET Blazor Server web application (for the UI and business logic).
+
+**Key Architecture Points:**
+- **Runtime:** Rust-based Tauri v1.8 application providing the native window, system integration, and IPC layer
+- **App:** .NET 9 Blazor Server application providing the UI and core functionality
+- **Communication:** The Rust runtime and .NET app communicate via HTTPS with TLS certificates generated at startup
+- **Providers:** Multi-provider architecture supporting OpenAI, Anthropic, Google, Mistral, Perplexity, self-hosted models, and others
+- **Plugin System:** Lua-based plugin system for language packs, configuration, and future assistant plugins
+
+## Building and Running
+
+### Prerequisites
+- .NET 9 SDK
+- Rust toolchain (stable)
+- Tauri v1.6.2 CLI: `cargo install --version 1.6.2 tauri-cli`
+- Tauri prerequisites (platform-specific dependencies)
+- **Note:** Development on Linux is discouraged due to complex Tauri dependencies that vary by distribution
+
+### One-Time Setup
+```bash
+cd app/Build
+dotnet run build
+```
+This builds the .NET app as a Tauri "sidecar" binary, which is required even for development.
+
+### Development Workflow
+Run these commands in separate terminals:
+
+**Terminal 1 - Start Rust runtime:**
+```bash
+cd runtime
+cargo tauri dev --no-watch
+```
+
+**Terminal 2 - Start .NET app:**
+```bash
+cd "app/MindWork AI Studio"
+dotnet run
+```
+
+The app will start in the Tauri window. Hot reload is supported for .NET code changes.
+
+### Building for Production
+```bash
+cd app/Build
+dotnet run build
+```
+Creates a release build for the current platform and architecture. Output is in `runtime/target/release/`.
+
+### Running Tests
+Currently no automated test suite exists in the repository.
+
+## Architecture Details
+
+### Rust Runtime (`runtime/`)
+**Entry point:** `runtime/src/main.rs`
+
+Key modules:
+- `app_window.rs` - Tauri window management, updater integration
+- `dotnet.rs` - Launches and manages the .NET sidecar process
+- `runtime_api.rs` - Rocket-based HTTPS API for .NET ↔ Rust communication
+- `certificate.rs` - Generates self-signed TLS certificates for secure IPC
+- `secret.rs` - Secure secret storage using OS keyring (Keychain/Credential Manager)
+- `clipboard.rs` - Cross-platform clipboard operations
+- `file_data.rs` - File processing for RAG (extracts text from PDF, DOCX, XLSX, PPTX, etc.)
+- `encryption.rs` - AES-256-CBC encryption for sensitive data
+- `pandoc.rs` - Integration with Pandoc for document conversion
+- `log.rs` - Logging infrastructure using `flexi_logger`
+
+### .NET App (`app/MindWork AI Studio/`)
+**Entry point:** `app/MindWork AI Studio/Program.cs`
+
+Key structure:
+- **Program.cs** - Bootstraps Blazor Server, configures Kestrel, initializes encryption and Rust service
+- **Provider/** - LLM provider implementations (OpenAI, Anthropic, Google, Mistral, etc.)
+  - `BaseProvider.cs` - Abstract base for all providers with streaming support
+  - `IProvider.cs` - Provider interface defining capabilities and streaming methods
+- **Chat/** - Chat functionality and message handling
+- **Assistants/** - Pre-configured assistants (translation, summarization, coding, etc.)
+  - `AssistantBase.razor` - Base component for all assistants
+- **Agents/** - contains all agents, e.g., for data source selection, context validation, etc.
+  - `AgentDataSourceSelection.cs` - Selects appropriate data sources for queries
+  - `AgentRetrievalContextValidation.cs` - Validates retrieved context relevance
+- **Tools/PluginSystem/** - Lua-based plugin system
+- **Tools/Services/** - Core background services (settings, message bus, data sources, updates)
+- **Tools/Rust/** - .NET wrapper for Rust API calls
+- **Settings/** - Application settings and data models
+- **Components/** - Reusable Blazor components
+- **Pages/** - Top-level page components
+
+### IPC Communication Flow
+1. Rust runtime starts and generates TLS certificate
+2. Rust starts internal HTTPS API on random port
+3. Rust launches .NET sidecar, passing: API port, certificate fingerprint, API token, secret key
+4. .NET reads environment variables and establishes secure HTTPS connection to Rust
+5. .NET requests an app port from Rust, starts Blazor Server on that port
+6. Rust opens Tauri webview pointing to localhost:app_port
+7. Bi-directional communication: .NET ↔ Rust via HTTPS API
+
+### Configuration and Metadata
+- `metadata.txt` - Build metadata (version, build time, component versions) read by both Rust and .NET
+- `startup.env` - Development environment variables (generated by build script)
+- `.NET project` reads metadata.txt at build time and injects as assembly attributes
+
+## Plugin System
+
+**Location:** `app/MindWork AI Studio/Plugins/`
+
+Plugins are written in Lua and provide:
+- **Language plugins** - I18N translations (e.g., German language pack)
+- **Configuration plugins** - Enterprise IT configurations for centrally managed providers, settings
+- **Future:** Assistant plugins for custom assistants
+
+**Example configuration plugin:** `app/MindWork AI Studio/Plugins/configuration/plugin.lua`
+
+Plugins can configure:
+- Self-hosted LLM providers
+- Update behavior
+- Preview features visibility
+- Preselected profiles
+- Chat templates
+
+## RAG (Retrieval-Augmented Generation)
+
+RAG integration is currently in development (preview feature). Architecture:
+- **External Retrieval Interface (ERI)** - Contract for integrating external data sources
+- **Data Sources** - Local files and external data via ERI servers
+- **Agents** - AI agents select data sources and validate retrieval quality
+- **Embedding providers** - Support for various embedding models
+- **Vector database** - Planned integration with Qdrant for vector storage
+- **File processing** - Extracts text from PDF, DOCX, XLSX via Rust runtime
+
+## Enterprise IT Support
+
+AI Studio supports centralized configuration for enterprise environments:
+- **Registry (Windows)** or **environment variables** (all platforms) specify configuration server URL and ID
+- Configuration downloaded as ZIP containing Lua plugin
+- Checks for updates every ~16 minutes via ETag
+- Allows IT departments to pre-configure providers, settings, and chat templates
+
+**Documentation:** `documentation/Enterprise IT.md`
+
+## Provider Confidence System
+
+Multi-level confidence scheme allows users to control which providers see which data:
+- Confidence levels: e.g. `NONE`, `LOW`, `MEDIUM`, `HIGH`, and some more granular levels
+- Each assistant/feature can require a minimum confidence level
+- Users assign confidence levels to providers based on trust
+
+**Implementation:** `app/MindWork AI Studio/Provider/Confidence.cs`
+
+## Dependencies and Frameworks
+
+**Rust:**
+- Tauri 1.8 - Desktop application framework
+- Rocket 0.5 - HTTPS API server
+- tokio - Async runtime
+- keyring - OS keyring integration
+- pdfium-render - PDF text extraction
+- calamine - Excel file parsing
+
+**.NET:**
+- Blazor Server - UI framework
+- MudBlazor 8.12 - Component library
+- LuaCSharp - Lua scripting engine
+- HtmlAgilityPack - HTML parsing
+- ReverseMarkdown - HTML to Markdown conversion
+
+## Security
+
+- **Encryption:** AES-256-CBC with PBKDF2 key derivation for sensitive data
+- **IPC:** TLS-secured communication with random ports and API tokens
+- **Secrets:** OS keyring for persistent secret storage (API keys, etc.)
+- **Sandboxing:** Tauri provides OS-level sandboxing
+
+## Release Process
+
+1. Create changelog file: `app/MindWork AI Studio/wwwroot/changelog/vX.Y.Z.md`
+2. Commit changelog
+3. Run from `app/Build`: `dotnet run release --action <patch|minor|major>`
+4. Create PR with version bump and changes
+5. After PR merge, maintainer creates git tag: `vX.Y.Z`
+6. GitHub Actions builds release binaries for all platforms
+7. Binaries uploaded to GitHub Releases
+
+## Important Development Notes
+
+- **File changes require Write/Edit tools** - Never use bash commands like `cat <<EOF` or `echo >`
+- **Spaces in paths** - Always quote paths with spaces in bash commands
+- **Debug environment** - Reads `startup.env` file with IPC credentials
+- **Production environment** - Runtime launches .NET sidecar with environment variables
+- **MudBlazor** - Component library requires DI setup in Program.cs
+- **Encryption** - Initialized before Rust service is marked ready
+- **Message Bus** - Singleton event bus for cross-component communication inside the .NET app