Reduce low-risk unused-symbol noise in core components (#316)

This first cleanup pass removes clearly unused imports and dead locals from a small set of components, and reconnects a few existing Props aliases to their component signatures so they stop surfacing as avoidable noise. The scope stays intentionally narrow to make the follow-up cleanup series easier to review and lower risk.

Constraint: Follow issue #314 with a components-only, low-risk first pass
Rejected: Broader sweep across commands/hooks/utils in the same PR | too much review surface for an initial cleanup pass
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep subsequent unused-code cleanups narrowly batched; treat signature/compatibility placeholders separately from straightforward import/alias cleanup
Tested: bun run build; bun run smoke; targeted noUnused grep for touched files via bun x tsc --noEmit --noUnusedLocals --noUnusedParameters --pretty false
Not-tested: full repo typecheck (baseline repo noise remains outside this narrow pass)

Co-authored-by: anandh8x <test@example.com>

src/components/PromptInput/IssueFlagBanner.tsx

@@ -1,7 +1,3 @@
-import * as React from 'react';
-import { FLAG_ICON } from '../../constants/figures.js';
-import { Box, Text } from '../../ink.js';
-
 /**
  * ANT-ONLY: Banner shown in the transcript that prompts users to report
  * issues via /issue. Appears when friction is detected in the conversation.