refactor(cli): split doctor/model-resolution and run/events into focused modules

Doctor checks:
- model-resolution-cache.ts, model-resolution-config.ts
- model-resolution-details.ts, model-resolution-effective-model.ts
- model-resolution-types.ts, model-resolution-variant.ts

Run events:
- event-formatting.ts, event-handlers.ts
- event-state.ts, event-stream-processor.ts

src/cli/doctor/checks/index.ts

@@ -15,6 +15,12 @@ export * from "./opencode"
 export * from "./plugin"
 export * from "./config"
 export * from "./model-resolution"
+export * from "./model-resolution-types"
+export * from "./model-resolution-cache"
+export * from "./model-resolution-config"
+export * from "./model-resolution-effective-model"
+export * from "./model-resolution-variant"
+export * from "./model-resolution-details"
 export * from "./auth"
 export * from "./dependencies"
 export * from "./gh"