feat: 90-day price range Y-axis scaling with breakthrough annotations

Backend:
- GET /api/market/prices/{ticker} now returns { bars, range_90d }
  with 90-day low/high computed from market_snapshots
- POST /api/market/backfill/{ticker} fetches 90 days of daily bars
  from Polygon and inserts missing bars into market_snapshots
- POST /api/market/backfill-all does the same for all active tickers

Frontend:
- Right Y-axis domain scaled to 90-day min/max (with 3% padding)
- Green dashed reference line at 90-day high
- Red dashed reference line at 90-day low
- Labels show exact price on each reference line
- Default limit bumped to 200 bars

frontend/src/api/hooks.ts

@@ -256,8 +256,13 @@ export interface MarketPrice {
   captured_at: string;
 }
 
-export function useMarketPrices(ticker: string | undefined, limit = 30) {
-  return useGet<MarketPrice[]>(
+export interface MarketPriceResponse {
+  bars: MarketPrice[];
+  range_90d: { low: number | null; high: number | null };
+}
+
+export function useMarketPrices(ticker: string | undefined, limit = 200) {
+  return useGet<MarketPriceResponse>(
     ['market-prices', ticker, limit],
     'query',
     `/api/market/prices/${ticker}?limit=${limit}`,
@@ -265,6 +270,18 @@ export function useMarketPrices(ticker: string | undefined, limit = 30) {
   );
 }
 
+/** Backfill 90 days of daily bars from Polygon for a single ticker. */
+export function useBackfillMarketPrices() {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (ticker: string) =>
+      apiPost<{ ticker: string; inserted: number; total_bars: number }>('query', `/api/market/backfill/${ticker}`, {}),
+    onSuccess: (_data, ticker) => {
+      qc.invalidateQueries({ queryKey: ['market-prices', ticker] });
+    },
+  });
+}
+
 export function useTrend(id: string | undefined) {
   return useGet<TrendSummary>(['trend', id], 'query', `/api/trends/${id}`, !!id);
 }

frontend/src/pages/CompanyDetail.tsx

@@ -22,7 +22,7 @@ import { DataTable, type Column } from '../components/DataTable';
 import type { Source, Alias, MacroImpactRecord, CompetitorRelationship, HistoricalPattern, CompetitiveSignal, CorporateDecision, TrendSummary, MarketPrice } from '../api/hooks';
 import {
   LineChart, Line, XAxis, YAxis, Tooltip, ResponsiveContainer,
-  CartesianGrid, Legend,
+  CartesianGrid, Legend, ReferenceLine,
 } from 'recharts';
 
 const sourceCols: Column<Source>[] = [
@@ -46,7 +46,9 @@ export function CompanyDetailPage() {
   const { data: trends } = useTrends({ ticker: company?.ticker, limit: 200 });
   const [selectedWindow, setSelectedWindow] = useState('7d');
   const { data: trendHistory } = useTrendHistory({ ticker: company?.ticker, window: selectedWindow, limit: 500 });
-  const { data: marketPrices } = useMarketPrices(company?.ticker, 200);
+  const { data: marketPriceData } = useMarketPrices(company?.ticker, 200);
+  const marketPrices = marketPriceData?.bars ?? [];
+  const range90d = marketPriceData?.range_90d ?? { low: null, high: null };
   const { data: positions } = usePositions(company?.ticker);
   const [tab, setTab] = useState<'trends' | 'sources' | 'aliases' | 'macro' | 'competitors' | 'patterns' | 'signals' | 'decisions'>('trends');
 
@@ -88,7 +90,7 @@ export function CompanyDetailPage() {
       {tab === 'trends' && (
         <div className="space-y-4">
           <PositionCard positions={positions ?? []} ticker={company.ticker} />
-          <TrendHistoryChart trends={trendHistory ?? []} latestTrends={trends ?? []} ticker={company.ticker} marketPrices={marketPrices ?? []} selectedWindow={selectedWindow} onWindowChange={setSelectedWindow} />
+          <TrendHistoryChart trends={trendHistory ?? []} latestTrends={trends ?? []} ticker={company.ticker} marketPrices={marketPrices} range90d={range90d} selectedWindow={selectedWindow} onWindowChange={setSelectedWindow} />
         </div>
       )}
 
@@ -680,7 +682,7 @@ function PositionCard({ positions, ticker }: { positions: import('../api/hooks')
   );
 }
 
-function TrendHistoryChart({ trends, latestTrends, ticker, marketPrices, selectedWindow, onWindowChange }: { trends: TrendSummary[]; latestTrends: TrendSummary[]; ticker: string; marketPrices: MarketPrice[]; selectedWindow: string; onWindowChange: (w: string) => void }) {
+function TrendHistoryChart({ trends, latestTrends, ticker, marketPrices, range90d, selectedWindow, onWindowChange }: { trends: TrendSummary[]; latestTrends: TrendSummary[]; ticker: string; marketPrices: MarketPrice[]; range90d: { low: number | null; high: number | null }; selectedWindow: string; onWindowChange: (w: string) => void }) {
 
   // Determine the time range for the selected window to filter data
   const windowHours: Record<string, number> = {
@@ -816,11 +818,34 @@ function TrendHistoryChart({ trends, latestTrends, ticker, marketPrices, selecte
                     tick={{ fill: '#e879f9', fontSize: 11 }}
                     tickLine={{ stroke: '#475569' }}
                     tickFormatter={(v) => `$${v}`}
-                    domain={['dataMin - 2', 'dataMax + 2']}
+                    domain={[
+                      range90d.low != null ? Math.floor(range90d.low * 0.97) : 'dataMin - 2',
+                      range90d.high != null ? Math.ceil(range90d.high * 1.03) : 'dataMax + 2',
+                    ]}
                   />
                 )}
                 <Tooltip content={TrendTooltip} />
                 <Legend wrapperStyle={{ color: '#94a3b8', fontSize: 12 }} />
+                {hasPrice && range90d.high != null && (
+                  <ReferenceLine
+                    yAxisId="right"
+                    y={range90d.high}
+                    stroke="#22c55e"
+                    strokeDasharray="6 3"
+                    strokeWidth={1.5}
+                    label={{ value: `90d High $${range90d.high.toFixed(2)}`, position: 'insideTopRight', fill: '#22c55e', fontSize: 10 }}
+                  />
+                )}
+                {hasPrice && range90d.low != null && (
+                  <ReferenceLine
+                    yAxisId="right"
+                    y={range90d.low}
+                    stroke="#ef4444"
+                    strokeDasharray="6 3"
+                    strokeWidth={1.5}
+                    label={{ value: `90d Low $${range90d.low.toFixed(2)}`, position: 'insideBottomRight', fill: '#ef4444', fontSize: 10 }}
+                  />
+                )}
                 <Line
                   yAxisId="left"
                   type="monotone"