fix(changes): resolve merge lint errors from origin/main sync

- DiffPane.tsx: gate the redacted view on the computed `hit` (the unused-var
  lint was the memo returning redactionHit: true unconditionally; now an
  unredacted payload short-circuits like the toggle-off path, and only an
  actual secret hit builds the masked copy)
- MarkdownHtml.tsx: drop the three dead imports (ComponentType,
  lazyChunkComponent, MermaidMarkdownProps) left by the mermaid-lazy merge

Typecheck clean; eslint clean on both files; 39 targeted tests pass.

src/client/MarkdownHtml.tsx

@@ -18,15 +18,13 @@ import { useLayoutEffect, useMemo, useRef } from 'react'
 import { createElement, type ReactNode } from 'react'
 import DOMPurify from 'dompurify'
 import { MarkdownText } from '@deepseek-ai/dsh-client-ui-primitives'
-import type { ComponentType } from 'react'
 import { markdownTextProps } from './markdown-labels.tsx'
-import { lazyChunkComponent } from './lazy-chunk.tsx'
 import { resolveLocalMediaDest } from './markdown-images.ts'
 import {
   analyzeHtmlSegment,
   type AnalyzedMarkdownHtml,
 } from './markdown-html.ts'
-import { splitMermaidBlocks, type MermaidMarkdownProps } from './mermaid-blocks.ts'
+import { splitMermaidBlocks } from './mermaid-blocks.ts'
 import type { SessionScope } from './api.ts'
 import css from './sidebar.module.css'
 

src/client/changes/DiffPane.tsx

@@ -177,6 +177,7 @@ export function DiffPane({ target, scope, height, onHeightCommit, onClose, onExp
     const mask = (text: string): string => redactText(path, text).text
     const hit = [opRaw.read, opRaw.content, opRaw.edit?.oldString, opRaw.edit?.newString, opRaw.errorText, priorRaw]
       .some((text) => text !== undefined && redactText(path, text).hit)
+    if (!hit) return { op: opRaw, prior: priorRaw, redactionHit: false }
     const redacted: FileOp = {
       ...opRaw,
       ...(opRaw.read !== undefined ? { read: mask(opRaw.read) } : {}),