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/trpc/router.ts

@@ -1897,9 +1897,32 @@ const institutionalRouter = router({
         if (cached) return { symbol, ratings: cached.ratings, consensus: cached.consensus, stale: true };
         return { symbol, ratings: [], consensus: null, error: result.error };
       }
-      return { symbol, ratings: result.ratings, consensus: result.consensus };
-    }),
-});
+       return { symbol, ratings: result.ratings, consensus: result.consensus };
+     }),
+
+   /** Short interest (shares short, % float, short ratio) from yahoo-finance2 defaultKeyStatistics. */
+   shortInterest: publicProcedure
+     .input(z.object({ symbol: z.string().min(1) }))
+     .query(async ({ ctx, input }) => {
+       const symbol = input.symbol.toUpperCase();
+       const k = `yfinance:shortinterest:${symbol}`;
+       const entry = await ctx.cache.get<unknown>(k);
+       const value = entry.value as Record<string, unknown> | null;
+       return {
+         symbol,
+         sharesShort: value ? (value.sharesShort as number | null) : null,
+         sharesShortPriorMonth: value ? (value.sharesShortPriorMonth as number | null) : null,
+         sharesPercentSharesOut: value ? (value.sharesPercentSharesOut as number | null) : null,
+         shortRatio: value ? (value.shortRatio as number | null) : null,
+         shortPercentOfFloat: value ? (value.shortPercentOfFloat as number | null) : null,
+         dateShortInterest: value ? (value.dateShortInterest as string | null) : null,
+         floatShares: value ? (value.floatShares as number | null) : null,
+         sharesOutstanding: value ? (value.sharesOutstanding as number | null) : null,
+         stale: entry.isStale,
+         provenance: entry.provenance,
+       };
+     }),
+};
 
 // ─── EDGAR / SEC Filings Router (Slice 6 / M6) ────────────────────────────