implement-featurelisted

# Implement Feature Implement the feature breadth first. Prove the complete path through the system before fully developing any isolated layer. ## Check the design Confirm that the design defines: * intended behavior * affected components * important interfaces and data changes * meaningful edge cases * compatibility constraints * rollout and rollback * test strategy * resolved decision ownership Return to design work if fundamental decisions remain unresolved. Do not silently make a material technical or product decision during implementation. ## Establish the skeleton Add the minimum structure needed for the feature to exist. This may include types, interfaces, routes, service boundaries, configuration, feature flags, migration scaffolding, and test fixtures. Keep the project compiling and tests runnable. Avoid building complete isolated components that are not yet connected to the real feature path. ## Build a thin end-to-end slice Implement the smallest representative happy path through the actual system. Exercise the real integration points where practical: * entry point * validation * authorization * domain or service logic * persistence or external dependency * response or presentation * one useful end-to-end or integration test Use this slice to verify that the design fits the codebase. ## Expand breadth first Add the remaining major behaviors as end-to-end increments before deeply polishing individual layers. Cover alternate valid paths, expected