refactor: remove ~275 lines of dead code and enable stricter tsconfig

- Delete unused src/cli/ui.ts, remove zod dependency, drop 4 dead functions (logError, handleToolError, getRetryDelay, displayTimingSummary)
- Remove 8 unused types/interfaces and 3 duplicate formatting utils from audit/utils.ts
- Narrow export surface: make 7 message-handler functions private, remove unused audit re-exports, unexport AgentDefinition and path constants
- Remove unused runClaudePrompt params (sessionMetadata, attemptNumber) and update caller
- Enable tsconfig noUnusedLocals, noUnusedParameters, noImplicitReturns, noImplicitOverride, noFallthroughCasesInSwitch

src/types/config.ts

@@ -29,10 +29,8 @@ export interface Rules {
 
 export type LoginType = 'form' | 'sso' | 'api' | 'basic';
 
-export type SuccessConditionType = 'url' | 'cookie' | 'element' | 'redirect';
-
 export interface SuccessCondition {
-  type: SuccessConditionType;
+  type: 'url' | 'cookie' | 'element' | 'redirect';
   value: string;
 }