Add Insiders tab with diverging bar chart and transaction table

- Backend: get_insider_transactions() in data_service (yfinance, 1hr TTL)
- Backend: InsidersResponse schema + GET /api/tickers/{symbol}/insiders
- Frontend: InsidersPage with 4-KPI strip, SVG diverging bar chart (),
  psm-insider transaction rows, pill filter toggles, shimmer skeleton,
  empty/error states
- Enable Insiders nav item (remove disabled flag)

1 files changed, 7 insertions, 2 deletions

diff --git a/frontend/lib/api.ts b/frontend/lib/api.ts
index 2c65ef2..84df997 100644
--- a/frontend/lib/api.ts
+++ b/frontend/lib/api.ts
@@ -1,4 +1,4 @@
-import type { FinancialsResponse, HistoryPoint, MarketIndex, RatiosResponse, SearchResult, TickerOverview, ValuationResponse, WatchlistResponse } from "@/types/api";
+import type { FinancialsResponse, HistoryPoint, InsidersResponse, MarketIndex, RatiosResponse, SearchResult, TickerOverview, ValuationResponse, WatchlistResponse } from "@/types/api";
 
 const API_BASE = (process.env.NEXT_PUBLIC_API_BASE_URL || "").trim().replace(/\/$/, "");
 
@@ -63,5 +63,10 @@ export const api = {
     return request<RatiosResponse>(
       `/api/tickers/${encodeURIComponent(symbol)}/ratios`
     );
-  }
+  },
+  insiders(symbol: string) {
+    return request<InsidersResponse>(
+      `/api/tickers/${encodeURIComponent(symbol)}/insiders`
+    );
+  },
 };