feat(ui): implement 'Twilight Velvet' dark theme and fix visibility issues

- Add 'Twilight Velvet' color palette to globals.css with OKLCH values
- Update SettingsPage headers, cards, and dialogs to use semantic theme variables
- Update HistoryCard, HistoryFeed, and DraftContent to support dark mode
- Update ProviderSelector and ProviderList to use custom card background (#2A2A3D)
- Add ThemeToggle component with improved visibility
- Ensure consistent use of 'bg-card', 'text-foreground', and 'text-muted-foreground'

src/app/(main)/history/page.tsx

@@ -0,0 +1,29 @@
+'use client';
+
+import { HistoryFeed } from '@/components/features/journal/HistoryFeed';
+import { HistoryDetailSheet } from '@/components/features/journal/HistoryDetailSheet';
+import { useHistoryStore } from '@/lib/store/history-store';
+
+export default function HistoryPage() {
+    const selectedDraft = useHistoryStore((s) => s.selectedDraft);
+    const closeDetail = useHistoryStore((s) => s.closeDetail);
+
+    return (
+        <div className="h-full flex flex-col bg-slate-50 relative">
+            <header className="px-4 py-4 bg-white border-b border-slate-200 shrink-0 sticky top-0 z-10">
+                <h1 className="text-xl font-bold font-serif text-slate-800">Your Journey</h1>
+            </header>
+
+            <HistoryFeed />
+
+            {/* Detail Sheet for viewing history items */}
+            {selectedDraft && (
+                <HistoryDetailSheet
+                    draft={selectedDraft}
+                    onClose={closeDetail}
+                    open={!!selectedDraft}
+                />
+            )}
+        </div>
+    );
+}