Initialize CBDD solution and add a .NET-focused gitignore for generated artifacts.

.agent/rules.md

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+# DocumentDb Project Rules
+
+## Performance Constraints
+
+### Tool Usage
+- **NEVER** use the `&` operator to combine commands in PowerShell (not supported). Use `;` or separate `run_command` calls instead.
+
+### Development
+- **ALWAYS** involve the user for refactoring tasks on sample and test files to focus on the core logic
+- Ask the user for build or test to get stack trace
+
+### Zero-Reflection Policy
+- **NEVER** use reflection in hot paths or runtime code
+- Source generators are preferred for code generation
+- All type information must be resolved at compile-time
+
+### Zero-Allocation Goals
+- Minimize heap allocations in critical paths
+- Use `Span<T>`, `ReadOnlySpan<T>`, and `Memory<T>` for buffer operations
+- Leverage stack allocation where appropriate (`stackalloc`)
+- Reuse buffers through `ArrayPool<T>` or custom pooling
+- Avoid LINQ in hot paths (use manual loops instead)
+- Prefer value types over reference types when possible
+- Use `ref struct` for temporary data structures
+
+### High-Performance Requirements
+- Memory-mapped files for efficient I/O
+- Lock-free or minimal locking strategies
+- Batch operations where possible
+- Optimize for CPU cache locality
+- Profile and benchmark all critical paths
+
+## Code Quality
+
+### Design Principles
+- Prefer composition over inheritance
+- Use interfaces for abstraction
+- Keep public API surface minimal and intentional
+- Use `readonly struct` for immutable value types
+
+### Testing
+- All public APIs must have unit tests
+- Performance-critical code must have benchmarks
+- Verify zero-allocation with BenchmarkDotNet memory diagnostics