refactor(ts): convert content pages to TSX (B13)

PrivacyPage (PrivacyDoc/PrivacySection + Record-typed iconByTitle), NotFoundPage
(typed GlitchDigit rAF loop, HTMLSpanElement ref), AboutPage (UpdateStatus/
AboutInfo + UpdateBadge), ReleaseNotesPage (ReleaseHistoryData, typed markdown
line parser). typecheck 0, lint 0 errors (35 warns), build green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/pages/AboutPage.tsx

@@ -1,4 +1,4 @@
-import React, { useCallback, useEffect, useState } from 'react';
+import { useCallback, useEffect, useState } from 'react';
 import { Link } from 'react-router-dom';
 import { ArrowLeft, ArrowUpCircle, CheckCircle2, Info, Loader2, Sparkles, AlertCircle } from 'lucide-react';
 import { api } from '@/api';
@@ -9,7 +9,22 @@ import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/com
 
 const REPOSITORY_URL = 'https://dream.scheller.ltd/null/BillTracker';
 
-function UpdateBadge({ status, loading }) {
+interface UpdateStatus {
+  has_update?: boolean;
+  latest_release_url?: string | null;
+  latest_version?: string;
+  up_to_date?: boolean | null;
+  error?: string | null;
+}
+
+interface AboutInfo {
+  version?: string;
+  name?: string;
+  description?: string;
+  stack?: { backend?: string; database?: string };
+}
+
+function UpdateBadge({ status, loading }: { status: UpdateStatus | null; loading: boolean }) {
   if (loading) {
     return (
       <span className="inline-flex items-center gap-1 text-xs text-muted-foreground/60">
@@ -55,15 +70,15 @@ function UpdateBadge({ status, loading }) {
 export default function AboutPage() {
   const { user } = useAuth();
 
-  const [about,         setAbout]         = useState(null);
+  const [about,         setAbout]         = useState<AboutInfo | null>(null);
   const [loading,       setLoading]       = useState(true);
-  const [updateStatus,  setUpdateStatus]  = useState(null);
+  const [updateStatus,  setUpdateStatus]  = useState<UpdateStatus | null>(null);
   const [updateLoading, setUpdateLoading] = useState(true);
 
   const load = useCallback(async () => {
     setLoading(true);
     try {
-      setAbout(await api.about());
+      setAbout(await api.about() as AboutInfo);
     } finally {
       setLoading(false);
     }
@@ -74,7 +89,7 @@ export default function AboutPage() {
   useEffect(() => {
     setUpdateLoading(true);
     api.updateStatus()
-      .then(setUpdateStatus)
+      .then(d => setUpdateStatus(d as UpdateStatus))
       .catch(() => setUpdateStatus(null))
       .finally(() => setUpdateLoading(false));
   }, []);

client/pages/NotFoundPage.tsx

@@ -5,8 +5,8 @@ import { Button } from '@/components/ui/button';
 import { useAuth } from '@/hooks/useAuth';
 
 // Animated digit — cycles through random numbers before settling
-function GlitchDigit({ value, delay = 0 }) {
-  const ref = useRef(null);
+function GlitchDigit({ value, delay = 0 }: { value: string; delay?: number }) {
+  const ref = useRef<HTMLSpanElement>(null);
 
   useEffect(() => {
     const el = ref.current;
@@ -15,20 +15,20 @@ function GlitchDigit({ value, delay = 0 }) {
     const frames = 14;
     const digits = '0123456789';
     let frame = 0;
-    let start = null;
+    let start: number | null = null;
 
-    function tick(ts) {
+    function tick(ts: number) {
       if (!start) start = ts + delay;
       const elapsed = ts - start;
       if (elapsed < 0) { requestAnimationFrame(tick); return; }
 
       if (frame < frames) {
-        el.textContent = digits[Math.floor(Math.random() * 10)];
+        el!.textContent = digits[Math.floor(Math.random() * 10)] ?? '0';
         frame++;
         setTimeout(() => requestAnimationFrame(tick), 40 + frame * 6);
       } else {
-        el.textContent = value;
-        el.classList.add('settled');
+        el!.textContent = value;
+        el!.classList.add('settled');
       }
     }
 

client/pages/PrivacyPage.tsx

@@ -1,15 +1,15 @@
-import React, { useCallback, useEffect, useState } from 'react';
+import { useCallback, useEffect, useState } from 'react';
 import { Link } from 'react-router-dom';
 import {
   ArrowLeft, BadgeCheck, Database, EyeOff, FileText, Fingerprint,
-  LockKeyhole, RadioTower, ShieldCheck, UserRoundCog,
+  LockKeyhole, RadioTower, ShieldCheck, UserRoundCog, type LucideIcon,
 } from 'lucide-react';
 import { api } from '@/api';
 import { useAuth } from '@/hooks/useAuth';
 import { Button } from '@/components/ui/button';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
 
-const iconByTitle = {
+const iconByTitle: Record<string, LucideIcon> = {
   Overview: ShieldCheck,
   'Data Collection': Database,
   'Version Checking': RadioTower,
@@ -21,15 +21,27 @@ const iconByTitle = {
   Contact: Fingerprint,
 };
 
+interface PrivacySection {
+  title: string;
+  items: string[];
+}
+
+interface PrivacyDoc {
+  name?: string;
+  summary?: string;
+  last_updated?: string;
+  sections?: PrivacySection[];
+}
+
 export default function PrivacyPage() {
   const { user } = useAuth();
-  const [privacy, setPrivacy] = useState(null);
+  const [privacy, setPrivacy] = useState<PrivacyDoc | null>(null);
   const [loading, setLoading] = useState(true);
 
   const load = useCallback(async () => {
     setLoading(true);
     try {
-      setPrivacy(await api.privacy());
+      setPrivacy(await api.privacy() as PrivacyDoc);
     } finally {
       setLoading(false);
     }

client/pages/ReleaseNotesPage.tsx

@@ -1,26 +1,32 @@
-import React, { useCallback, useEffect, useState } from 'react';
+import { useCallback, useEffect, useState } from 'react';
 import { Link } from 'react-router-dom';
 import { ArrowLeft, RefreshCw } from 'lucide-react';
 import { toast } from 'sonner';
 import { api } from '@/api';
-import { cn } from '@/lib/utils';
+import { cn, errMessage } from '@/lib/utils';
 import { Button } from '@/components/ui/button';
 import { MarkdownText } from '@/components/MarkdownText';
 
-function formatDateTime(value) {
+interface ReleaseHistoryData {
+  history?: string;
+  version?: string;
+  updated_at?: string;
+}
+
+function formatDateTime(value: string | null | undefined): string | null {
   if (!value) return null;
   const date = new Date(value);
   if (Number.isNaN(date.getTime())) return value;
   return date.toLocaleString();
 }
 
-function parseImageLine(line) {
+function parseImageLine(line: string): { alt: string; src: string } | null {
   const match = line.match(/^!\[([^\]\n]*)\]\(([^)\s]+)\)$/);
   if (!match) return null;
-  return { alt: match[1], src: match[2] };
+  return { alt: match[1] ?? '', src: match[2] ?? '' };
 }
 
-function HistoryLine({ line, index }) {
+function HistoryLine({ line, index }: { line: string; index: number }) {
   const trimmed = line.trim();
   const image = parseImageLine(trimmed);
 
@@ -82,18 +88,18 @@ function HistoryLine({ line, index }) {
 }
 
 export default function ReleaseNotesPage() {
-  const [data, setData] = useState(null);
+  const [data, setData] = useState<ReleaseHistoryData | null>(null);
   const [loading, setLoading] = useState(true);
-  const [error, setError] = useState(null);
+  const [error, setError] = useState<string | null>(null);
 
   const load = useCallback(async () => {
     setLoading(true);
     setError(null);
     try {
-      setData(await api.releaseHistory());
+      setData(await api.releaseHistory() as ReleaseHistoryData);
     } catch (err) {
-      setError(err.message || 'Failed to load release notes.');
-      toast.error(err.message || 'Failed to load release notes.');
+      setError(errMessage(err, 'Failed to load release notes.'));
+      toast.error(errMessage(err, 'Failed to load release notes.'));
     } finally {
       setLoading(false);
     }