feat: short interest panel Phase 1 Yahoo Finance

- Add short_interest TtlClass (24h) to CacheRepository.ts with shortInterestHandler KindHandler (kv_cache JSON pattern), register in HANDLERS and del switch case
- Add case 'shortinterest' to YFinanceAdapter.fetchOne using quoteSummary(defaultKeyStatistics): parses sharesShort, shortPercentOfFloat, shortRatio, dateShortInterest, sharesShortPriorMonth, floatShares, sharesOutstanding
- Add institutional.shortInterest tRPC procedure (cache-read pattern, returns stale flag + provenance)
- Add api.institutional.shortInterest to frontend trpc client
- Create ShortInterestPanel.tsx: mirrors AnalystRatings pattern with loading/error/retry states, formatted shares/ratio/percentage display with source date
- Mount ShortInterestPanel on overview page after AnalystRatings

app/server/src/adapters/YFinanceAdapter.ts

@@ -45,6 +45,34 @@ export class YFinanceAdapter implements SourceFetch {
         const raw = await yf.quoteSummary(id, { modules: ['summaryProfile'] });
         return { value: parseSymbol(raw, id), ttlClass: 'symbol_meta', provenance: { fetchedAt, sourceKind: 'yfinance', rawSourceId: id } };
       }
+      case 'shortinterest': {
+        const raw = await yf.quoteSummary(id, { modules: ['defaultKeyStatistics'] });
+        const stats = (raw as Record<string, unknown>)?.defaultKeyStatistics as Record<string, unknown> | undefined;
+        if (!stats) throw new Error('No defaultKeyStatistics module available');
+        const parseNum = (v: unknown): number | null => {
+          if (v === null || v === undefined) return null;
+          if (typeof v === 'number') return v;
+          const s = String(v).replace(/[,]/g, '');
+          const n = parseFloat(s);
+          return Number.isNaN(n) ? null : n;
+        };
+        return {
+          value: {
+            sharesShort: parseNum(stats.sharesShort),
+            sharesShortPriorMonth: parseNum(stats.sharesShortPriorMonth),
+            sharesShortPreviousMonthDate: stats.sharesShortPreviousMonthDate ? String(stats.sharesShortPreviousMonthDate).slice(0, 10) : null,
+            dateShortInterest: stats.dateShortInterest ? String(stats.dateShortInterest).slice(0, 10) : null,
+            sharesPercentSharesOut: parseNum(stats.sharesPercentSharesOut),
+            shortRatio: parseNum(stats.shortRatio),
+            shortPercentOfFloat: parseNum(stats.shortPercentOfFloat),
+            floatShares: parseNum(stats.floatShares),
+            sharesOutstanding: parseNum(stats.sharesOutstanding),
+            sourceTickerKind: (stats as Record<string, unknown>).optionMethod?.toString() ?? null,
+          },
+          ttlClass: 'short_interest',
+          provenance: { fetchedAt, sourceKind: 'yfinance', rawSourceId: id },
+        };
+      }
       default: throw new Error(`YFinanceAdapter: unknown kind '${kind}'`);
     }
   }