feat: AI course content expansion (40 lessons) + sync/UX/typography fixes

scripts/auditFormulas.mjs

@@ -0,0 +1,41 @@
+// 公式审计：扫描全部 10 章课程数据里的 $$/$ 公式，用 KaTeX 严格解析找出渲染失败项
+import katex from 'katex'
+import { NLP_LESSONS } from '../src/data/ai/chapters/nlp.js'
+import { CV_LESSONS } from '../src/data/ai/chapters/cv.js'
+import { RL_LESSONS } from '../src/data/ai/chapters/rl.js'
+import { LLM_LESSONS } from '../src/data/ai/chapters/llm.js'
+import { OPTIM_LESSONS } from '../src/data/ai/chapters/optim.js'
+import { ML_LESSONS } from '../src/data/ai/chapters/ml.js'
+import { DL_LESSONS } from '../src/data/ai/chapters/dl.js'
+import { OR_LESSONS } from '../src/data/ai/chapters/or.js'
+import { FEATURE_LESSONS } from '../src/data/ai/chapters/feature.js'
+import { INFO_THEORY_LESSONS } from '../src/data/ai/chapters/it.js'
+
+const groups = {
+  nlp: NLP_LESSONS, cv: CV_LESSONS, rl: RL_LESSONS, llm: LLM_LESSONS,
+  optim: OPTIM_LESSONS, ml: ML_LESSONS, dl: DL_LESSONS, or: OR_LESSONS,
+  feature: FEATURE_LESSONS, it: INFO_THEORY_LESSONS,
+}
+let bad = 0
+
+for (const [name, lessons] of Object.entries(groups)) {
+  for (const lesson of lessons) {
+    const theory = lesson.theory || ''
+    const formulas = []
+    for (const m of theory.matchAll(/\$\$([\s\S]+?)\$\$/g)) formulas.push({ tex: m[1], mode: 'block' })
+    const noBlocks = theory.replace(/\$\$[\s\S]+?\$\$/g, '')
+    for (const m of noBlocks.matchAll(/\$([^$\n]+?)\$/g)) formulas.push({ tex: m[1], mode: 'inline' })
+
+    for (const f of formulas) {
+      try {
+        katex.renderToString(f.tex, { displayMode: f.mode === 'block', throwOnError: true, strict: false })
+      } catch (err) {
+        bad++
+        console.log(`[${name}] ${lesson.id} (${f.mode}):`)
+        console.log(`  TEX: ${f.tex.slice(0, 120)}`)
+        console.log(`  ERR: ${String(err.message).slice(0, 160)}`)
+      }
+    }
+  }
+}
+console.log(bad === 0 ? 'ALL FORMULAS OK' : `${bad} broken formulas found`)

src/components/StepController.jsx

@@ -68,8 +68,15 @@ export default function StepController({
 }) {
   const scrubberRef = useRef(null)
   const isDragging = useRef(false)
+  // 拖拽期间挂在 window 上的监听器的卸载函数；组件若在拖拽中途 unmount，
+  // 由下面的 useEffect cleanup 兜底移除，避免监听器泄漏。
+  const detachDragListeners = useRef(null)
   const isPhone = useIsPhone()
 
+  useEffect(() => {
+    return () => { detachDragListeners.current?.() }
+  }, [])
+
   // 活跃实例登记:挂载即认领;卸载时若仍是自己则释放
   const idRef = useRef(null)
   if (!idRef.current) idRef.current = Symbol('step-controller')
@@ -102,14 +109,18 @@ export default function StepController({
     seek(posToStep(e.clientX))
     window.addEventListener('mousemove', handleScrubberMouseMove)
     window.addEventListener('mouseup', handleScrubberMouseUp)
+    detachDragListeners.current = () => {
+      window.removeEventListener('mousemove', handleScrubberMouseMove)
+      window.removeEventListener('mouseup', handleScrubberMouseUp)
+      detachDragListeners.current = null
+    }
   }
   function handleScrubberMouseMove(e) {
     if (isDragging.current) seek(posToStep(e.clientX))
   }
   function handleScrubberMouseUp() {
     isDragging.current = false
-    window.removeEventListener('mousemove', handleScrubberMouseMove)
-    window.removeEventListener('mouseup', handleScrubberMouseUp)
+    detachDragListeners.current?.()
   }
   function handleScrubberTouch(e) {
     seek(posToStep(e.touches[0].clientX))

src/components/learning/AlgorithmTabs.jsx

@@ -1,4 +1,5 @@
 import { lazy, Suspense, useEffect, useState, useCallback, memo } from 'react'
+import ErrorBoundary from '../ErrorBoundary'
 import { Prose } from './Section'
 import CodeBlock from './CodeBlock'
 import ComplexityCards from './ComplexityCards'
@@ -157,9 +158,13 @@ const AlgorithmTabs = memo(function AlgorithmTabs({ algo }) {
 
         {active === 'notes' && (
           <Panel id="notes" title={null}>
-            <Suspense fallback={<div className="text-sm text-[var(--text-tertiary)]">正在加载笔记...</div>}>
-              <Notes slug={algo.slug} />
-            </Suspense>
+            <ErrorBoundary fallback={
+              <div className="text-sm text-fg-muted">笔记模块加载失败，请刷新页面重试。</div>
+            }>
+              <Suspense fallback={<div className="text-sm text-fg-faint">正在加载笔记...</div>}>
+                <Notes slug={algo.slug} />
+              </Suspense>
+            </ErrorBoundary>
           </Panel>
         )}
       </div>

src/contexts/ProgressContext.jsx

@@ -109,6 +109,16 @@ export function ProgressProvider({ children }) {
     return () => { cancelled = true }
   }, [userId, store])
 
+  // 页面隐藏 / 卸载时立即冲刷防抖队列，避免刚产生的进度变更丢在 pending 里。
+  // pagehide 在移动端比 beforeunload 更可靠；flush 是 best-effort，失败也不影响
+  // 本地副本（下次登录 syncWithRemote 会整体合并推回）。
+  useEffect(() => {
+    if (!userId) return
+    const onPageHide = () => { sync.flushNow() }
+    window.addEventListener('pagehide', onPageHide)
+    return () => window.removeEventListener('pagehide', onPageHide)
+  }, [userId])
+
   // 登录态下订阅 realtime
   useEffect(() => {
     if (!userId) return