feat(HAI-027): add configurable test and build commands to settings

- Add testCommand and buildCommand optional fields to Settings type
- Inject configured commands into triage agent context for task specs
- Add test/build command input fields to the settings modal UI
- Remove legacy executor-level command handling in favor of triage injection
- Add triage tests covering command injection behavior

packages/core/src/types.ts

@@ -62,6 +62,10 @@ export interface Settings {
   /** Shell command to run inside each new worktree immediately after creation.
    *  Useful for project-specific setup (e.g. `pnpm install`, `cp .env.local .env`). */
   worktreeInitCommand?: string;
+  /** Custom test command for the project (e.g. "pnpm test") */
+  testCommand?: string;
+  /** Custom build command for the project (e.g. "pnpm build") */
+  buildCommand?: string;
 }
 
 export const DEFAULT_SETTINGS: Settings = {