Add step between exact ID match and forward fuzzy match that checks if registry model ID starts with the requested name. Fixes models like 'gpt-5.4-mini' not matching 'gpt-5.4-mini-2026-04-01' in registry.
- Split 1474-line dashboard.go into 5 domain files (clients, providers, users, system) - Unit tests for ModelRegistry.FindModel and CalculateCost - go mod tidy + verify (deps clean) - .gitignore excludes tool cache dirs (.pi-lens/, .opencode/)