v0.9.0: in-app auto-updater, ship toggle split, stable entity IDs, performance fixes

New features:
- In-app auto-updater with confirmation dialog, manual download fallback,
  restart polling, and protected file safety net
- Ship layers split into 4 independent toggles (Military/Carriers, Cargo/Tankers,
  Civilian, Cruise/Passenger) with per-category counts
- Stable entity IDs using MMSI/callsign instead of volatile array indices
- Dismissible threat alert bubbles (session-scoped, survives data refresh)

Performance:
- GDELT title fetching is now non-blocking (background enrichment)
- Removed duplicate startup fetch jobs
- Docker healthcheck start_period 15s → 90s

Bug fixes:
- Removed fake intelligence assessment generator (OSINT-only policy)
- Fixed carrier tracker GDELT 429/TypeError crash
- Fixed ETag collision (full payload hash)
- Added concurrent /api/refresh guard

Contributors: @imqdcr (ship split + stable IDs), @csysp (dismissible alerts, PR #48)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Former-commit-id: a2c4c67da54345393f70a9b33b52e7e4fd6c049f

frontend/src/lib/DashboardDataContext.tsx

@@ -0,0 +1,30 @@
+"use client";
+
+import React, { createContext, useContext } from "react";
+
+interface DashboardDataContextValue {
+    data: any;
+    selectedEntity: { id: string | number; type: string; extra?: any } | null;
+    setSelectedEntity: (entity: { id: string | number; type: string; extra?: any } | null) => void;
+}
+
+const DashboardDataContext = createContext<DashboardDataContextValue | null>(null);
+
+export function DashboardDataProvider({
+    data,
+    selectedEntity,
+    setSelectedEntity,
+    children,
+}: DashboardDataContextValue & { children: React.ReactNode }) {
+    return (
+        <DashboardDataContext.Provider value={{ data, selectedEntity, setSelectedEntity }}>
+            {children}
+        </DashboardDataContext.Provider>
+    );
+}
+
+export function useDashboardData(): DashboardDataContextValue {
+    const ctx = useContext(DashboardDataContext);
+    if (!ctx) throw new Error("useDashboardData must be used within DashboardDataProvider");
+    return ctx;
+}