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+# Copilot Instructions
+
+This project features an **ASP.NET Core** backend (REST API) and a **Svelte 5 TypeScript** frontend (SPA). All contributions should respect existing formatting and conventions specified in the project’s `.editorconfig`.
+
+---
+
+## 1. General Coding Guidelines
+
+- **Maintain File Style & Minimal Diffs:**
+  - Match the code style of the file. When unsure, use the style defined in the `.editorconfig`.
+  - Keep diffs as small as possible. Preserve existing formatting, including extra spaces and comments.
+
+- **Complete, Clear, and Modern Code:**
+  - Write complete code for every step—no placeholders or TODOs.
+  - Prioritize readability by using modern language features, clear naming, and clean code practices.
+  - It's acceptable to employ defensive coding practices when needed to handle unexpected scenarios gracefully.
+
+- **Design Principles:**
+  - Follow SOLID, DRY, and overall clean code principles.
+  - Remove unused code; simplicity equals maintainability.
+
+- **Behavioral Changes:**
+  - Flag any user-visible changes and review them carefully.
+
+---
+
+## 2. Frontend Guidelines (Svelte 5 / TypeScript SPA)
+
+- **Framework & Best Practices:**
+  - Built with Svelte 5 in SPA mode using TypeScript and Tailwind CSS.
+  - Adhere to modern ES6 best practices and the ESLint recommended configuration ([standardjs](https://standardjs.com)).
+
+- **Architecture & Components:**
+  - Utilize the Composite Component Pattern (similar to shadcn-svelte).
+  - Organize code using vertical slices for features with a shared folder for common components.
+  - **Avoid** using any server-side Svelte features.
+
+- **UI, Accessibility, and Navigation:**
+  - Ensure excellent keyboard navigation for all front-end interactions.
+  - Leverage shadcn-svelte components, which are built on [bits-ui](https://bits-ui.com/docs/llms.txt).
+  - Build forms using shadcn-svelte forms & superforms, and validate with class-validator.
+  - For icons use lucide-svelte.
+  - Follow mobile-first responsive design, semantic HTML, and secure WCAG 2.2 Level AA compliance.
+
+- **Testing:**
+  - Unit Testing: Vitest
+  - Component Testing: Testing Library
+  - E2E Testing: Playwright
+
+- **Reference:**
+  - Svelte 5 SPA guidelines: [https://svelte.dev/llms-full.txt](https://svelte.dev/llms-full.txt)
+
+---
+
+## 3. Backend Guidelines (ASP.NET Core / C#)
+
+- **Framework & Language Features:**
+  - Developed with the latest ASP.NET Core and C#.
+  - Enable Nullable Reference Types.
+
+- **Coding Conventions & Best Practices:**
+  - Follow guidelines from the `.editorconfig` and Microsoft's [coding conventions](https://learn.microsoft.com/en-us/dotnet/csharp/fundamentals/coding-style/coding-conventions).
+  - Adhere to Microsoft's best practices for ASP.NET Core development and [unit testing with xUnit](https://learn.microsoft.com/en-us/dotnet/core/testing/unit-testing-best-practices).
+
+- **Architecture Considerations:**
+  - Factor in the inherent challenges of distributed computing when designing features.
+
+---
+
+## 4. Performance
+
+- **Optimizations:**
+  - Lazy load components when possible.
+  - Optimize images and assets.
+  - Employ effective caching strategies.
+
+---
+
+## 5. Security
+
+- **Data Protection & Validation:**
+  - Sanitize all user inputs and validate data rigorously.
+  - Follow OWASP guidelines and implement a robust Content Security Policy.
+  - Embrace Shift-Left security practices.
+
+---
+
+## 6. Code Reviews
+
+- **Focus Areas:**
+  - Review for complexity, consistency, duplication, and adherence to best practices.
+  - Verify robust error handling and the effectiveness of defensive coding when applied.
+
+---
+
+## 7. Debugging Guidelines
+
+1. **Reproduce** the issue using minimal steps and code.
+2. **Understand** the core problem.
+3. **Hypothesize** the root cause.
+4. **Test & Verify** the solution.
+5. **Document** the fix and any adjustments made.
+
+---
+
+## 8. Project Structure
+
+```plaintext
+project-root/
+├── build                                           # Build files
+├── docker                                          # Docker files
+├── k8s                                             # Kubernetes files
+├── samples
+├── src
+│   ├── Exceptionless.AppHost                       # Aspire
+│   ├── Exceptionless.Core                          # Domain
+│   ├── Exceptionless.EmailTemplates                # Email Templates
+│   ├── Exceptionless.Insulation                    # Concrete Implementations
+│   ├── Exceptionless.Job                           # ASP.NET Core Jobs
+│   ├── Exceptionless.Web                           # ASP.NET Core Web Application
+│   │   ├── ClientApp                               # Frontend SvelteKit Spa Application
+│   │   │   ├── api-templates                       # API templates for generated code using OpenApi
+│   │   │   ├── e2e
+│   │   │   ├── src                                 # JavaScript SvelteKit application
+│   │   │   │   ├── lib
+│   │   │   │   │   ├── assets                      # Static assets
+│   │   │   │   │   ├── features                    # Vertical Sliced Features, each folder corresponds to an api controller
+│   │   │   │   │   │   ├── events                  # Event features (related to Events Controller)
+│   │   │   │   │   │   │   ├── components
+│   │   │   │   │   │   │   └── models
+│   │   │   │   │   │   ├── organizations
+│   │   │   │   │   │   ├── projects
+│   │   │   │   │   │   │   └── components
+│   │   │   │   │   │   ├── shared                  # Shared components used by all other features
+│   │   │   │   │   │   │   ├── api
+│   │   │   │   │   │   │   ├── components
+│   │   │   │   │   │   │   └── models
+│   │   │   │   │   │   ├── stacks
+│   │   │   │   │   │   │   └── components
+│   │   │   │   │   ├── generated                   # Generated code
+│   │   │   │   │   ├── hooks                       # Client hooks
+│   │   │   │   │   └── utils                       # Utility functions
+│   │   │   │   └── routes                          # Application routes
+│   │   │   │       ├── (app)
+│   │   │   │       │   ├── account
+│   │   │   │       │   └── stream
+│   │   │   │       ├── (auth)
+│   │   │   │       │   ├── login
+│   │   │   │       │   └── logout
+│   │   │   │       └── status
+│   │   │   └── static                              # Static assets
+│   │   ├── ClientApp.angular                       # Legacy Angular Client Application (Ignore)
+│   │   ├── Controllers                             # ASP.NET Core Web API Controllers
+│   └── tests                                       # ASP.NET Core Unit and Integration Tests
+```
+
+---
+
+### Additional Considerations
+
+- **Expanding the Guidelines:**
+  As the project evolves, consider including sample code snippets, decision flowcharts, or ASCII diagrams to clarify more complex guidelines.
+
+- **Continuous Improvement:**
+  Regularly review and update these guidelines to stay aligned with evolving best practices and emerging technologies.
+
+- **Thoughtful Contribution:**
+  Always strive to deliver code that not only functions well but also advances the overall maintainability and quality of the project.
+
+Let's keep pushing for clarity, usability, and excellence—both in code and user experience.