docs: establish codebase conventions and developer guidelines

.gitignore

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 # Aider related generated files
 .aider-context
-CONVENTIONS.md
 bin
 .env
 

CONVENTIONS.md

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+# CLAUDE.md - Developer Guidelines for SNRD Codebase
+
+## Build & Test Commands
+- `make build` - Build application binary
+- `make install` - Install application
+- `make test` - Run unit tests
+- `make test-unit` - Run all unit tests
+- `make test-race` - Run tests with race detection
+- `make test-cover` - Run tests with coverage
+- `make lint` - Run golangci-lint and formatting checks
+- `make format` - Format code using gofumpt
+- `make proto-gen` - Generate Protobuf files
+- `make testnet` - Setup and run local testnet with IBC
+
+## Code Style Guidelines
+- **Imports**: Group by standard library, third-party, then project-specific with blank lines between
+- **Error Handling**: Use custom errors from `types/errors.go` with `sdkerrors.Register` and prefix errors with `Err`
+- **Naming**: Use camelCase for variables, PascalCase for functions/exported types
+- **Organization**: Follow Cosmos SDK module pattern (`x/{module}/`, `types/`, `keeper/`)
+- **Documentation**: Use standard Go doc comments, document public APIs thoroughly
+- **Types**: Prefer explicit types over interface{}, use pointers for mutable state
+- **Design**: Follow dependency injection pattern for module components
+- **Formatting**: Run `make format` before committing
+
+Follows standard Go conventions and Cosmos SDK patterns with clear organization and consistent error handling.