v0.9.5: The Voltron Update — modular architecture, stable IDs, parallelized boot

- Parallelized startup (60s → 15s) via ThreadPoolExecutor
- Adaptive polling engine with ETag caching (no more bbox interrupts)
- useCallback optimization for interpolation functions
- Sliding LAYERS/INTEL edge panels replace bulky Record Panel
- Modular fetcher architecture (flights, geo, infrastructure, financial, earth_observation)
- Stable entity IDs for GDELT & News popups (PR #63, credit @csysp)
- Admin auth (X-Admin-Key), rate limiting (slowapi), auto-updater
- Docker Swarm secrets support, env_check.py validation
- 85+ vitest tests, CI pipeline, geoJSON builder extraction
- Server-side viewport bbox filtering reduces payloads 80%+

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

Former-commit-id: f2883150b5bc78ebc139d89cc966a76f7d7c0408

frontend/src/__tests__/utils/solarTerminator.test.ts

@@ -0,0 +1,86 @@
+import { describe, it, expect } from 'vitest';
+import { computeNightPolygon } from '@/utils/solarTerminator';
+
+/** Extract polygon ring from result (type-narrowing helper) */
+function getRing(result: GeoJSON.FeatureCollection): number[][] {
+  const geom = result.features[0].geometry;
+  if (geom.type !== 'Polygon') throw new Error('Expected Polygon geometry');
+  return geom.coordinates[0];
+}
+
+describe('computeNightPolygon', () => {
+  // ─── Structure validation ────────────────────────────────────────────────
+
+  it('returns a valid GeoJSON FeatureCollection', () => {
+    const result = computeNightPolygon();
+    expect(result.type).toBe('FeatureCollection');
+    expect(result.features).toHaveLength(1);
+    expect(result.features[0].type).toBe('Feature');
+    expect(result.features[0].geometry.type).toBe('Polygon');
+  });
+
+  it('polygon has at least 360 vertices (one per degree of longitude)', () => {
+    const ring = getRing(computeNightPolygon());
+    // 361 terminator points + 2 closing corners + 1 ring-close = ≥364
+    expect(ring.length).toBeGreaterThanOrEqual(364);
+  });
+
+  it('polygon ring is closed (first and last points match)', () => {
+    const ring = getRing(computeNightPolygon());
+    expect(ring[ring.length - 1]).toEqual(ring[0]);
+  });
+
+  // ─── Coordinate bounds ───────────────────────────────────────────────────
+
+  it('all coordinates are within valid lat/lng bounds', () => {
+    const ring = getRing(computeNightPolygon());
+    for (const [lng, lat] of ring) {
+      expect(lng).toBeGreaterThanOrEqual(-180);
+      expect(lng).toBeLessThanOrEqual(180);
+      expect(lat).toBeGreaterThanOrEqual(-85);
+      expect(lat).toBeLessThanOrEqual(85);
+    }
+  });
+
+  // ─── Deterministic for same input ────────────────────────────────────────
+
+  it('returns identical result for the same date', () => {
+    const date = new Date('2024-06-21T12:00:00Z');
+    const result1 = computeNightPolygon(date);
+    const result2 = computeNightPolygon(date);
+    expect(result1).toEqual(result2);
+  });
+
+  // ─── Seasonal behavior ──────────────────────────────────────────────────
+
+  it('equinox produces roughly symmetric polygon', () => {
+    const equinox = new Date('2024-03-20T12:00:00Z');
+    const ring = getRing(computeNightPolygon(equinox));
+    const lats = ring.map(([, lat]: number[]) => lat);
+    const maxLat = Math.max(...lats);
+    const minLat = Math.min(...lats);
+    expect(maxLat).toBeGreaterThan(50);
+    expect(minLat).toBeLessThan(-50);
+  });
+
+  it('summer solstice shifts night polygon southward', () => {
+    const summer = new Date('2024-06-21T00:00:00Z');
+    const ring = getRing(computeNightPolygon(summer));
+    const terminatorLats = ring
+      .filter(([lng]: number[]) => lng >= -180 && lng <= 180)
+      .slice(0, 361)
+      .map(([, lat]: number[]) => lat);
+    const avgLat = terminatorLats.reduce((a: number, b: number) => a + b, 0) / terminatorLats.length;
+    expect(avgLat).toBeLessThan(15);
+  });
+
+  // ─── Different times produce different results ──────────────────────────
+
+  it('produces different polygons for different times of day', () => {
+    const morning = new Date('2024-06-21T06:00:00Z');
+    const evening = new Date('2024-06-21T18:00:00Z');
+    const ringM = getRing(computeNightPolygon(morning));
+    const ringE = getRing(computeNightPolygon(evening));
+    expect(ringM[0]).not.toEqual(ringE[0]);
+  });
+});