Fase 1b: cableado del matcher (ingesta polling, runner shadow/full, comparador)

- config: bloque matcher (MATCHER_MODE off/shadow/full, IRON_PASSWORD, audiencia,
  poll, batch) + validacion
- db: colecciones subscriptions/activefires/notifications_shadow/matcher_state +
  ensureMatcherIndexes (2dsphere en notifications_shadow para el dedupe 500m)
- matcher/context: MatchContext sobre Mongo real (candidatas geo $near 1000km +
  audiencia; dedupe geo $near 500m; lang del owner)
- matcher/ingest: polling de activefires por createdAt>checkpoint (Mongo 3.2 sin
  change streams), checkpoint persistido en matcher_state
- matcher/runner: loop shadow(->notifications_shadow)/full(->notifications),
  idempotente por dedupe+checkpoint
- matcher/compare: comparador de shadow (shadowOnly=spam, realOnly=faltantes,
  contentMismatches) — el gate antes del cutover
- index: arranca el matcher; fake-repo ampliado (upsert, sort, $gt/$lt)
- docs/env/README actualizados

73 tests en verde, typecheck y build OK.

test/compare.test.ts

@@ -0,0 +1,52 @@
+import { describe, expect, it } from 'vitest';
+import { ObjectId } from 'mongodb';
+import { compareShadow, notifKey } from '../src/matcher/compare.js';
+import type { NotificationDoc } from '../src/types.js';
+
+function n(userId: string, lon: number, lat: number, content = 'c'): NotificationDoc {
+  return {
+    _id: new ObjectId(),
+    userId,
+    content,
+    geo: { type: 'Point', coordinates: [lon, lat] },
+    type: 'mobile',
+    when: new Date('2026-07-13T12:00:00Z'),
+    sealed: 's',
+  };
+}
+
+describe('compareShadow', () => {
+  it('matches identical sets', () => {
+    const a = [n('u1', -3.7, 40.4), n('u2', -4, 41)];
+    const b = [n('u1', -3.7, 40.4), n('u2', -4, 41)];
+    const diff = compareShadow(a, b);
+    expect(diff.matched).toBe(2);
+    expect(diff.shadowOnly).toHaveLength(0);
+    expect(diff.realOnly).toHaveLength(0);
+  });
+
+  it('flags shadowOnly (spam risk) when we generate an extra notification', () => {
+    const shadow = [n('u1', -3.7, 40.4), n('u3', -5, 42)];
+    const real = [n('u1', -3.7, 40.4)];
+    const diff = compareShadow(shadow, real);
+    expect(diff.shadowOnly).toEqual([notifKey(n('u3', -5, 42))]);
+    expect(diff.realOnly).toHaveLength(0);
+  });
+
+  it('flags realOnly (missing) when node-red had one we do not', () => {
+    const shadow = [n('u1', -3.7, 40.4)];
+    const real = [n('u1', -3.7, 40.4), n('u2', -4, 41)];
+    const diff = compareShadow(shadow, real);
+    expect(diff.realOnly).toEqual([notifKey(n('u2', -4, 41))]);
+    expect(diff.shadowOnly).toHaveLength(0);
+  });
+
+  it('reports content mismatches on matched keys', () => {
+    const shadow = [n('u1', -3.7, 40.4, 'nuevo texto')];
+    const real = [n('u1', -3.7, 40.4, 'viejo texto')];
+    const diff = compareShadow(shadow, real);
+    expect(diff.matched).toBe(1);
+    expect(diff.contentMismatches).toHaveLength(1);
+    expect(diff.contentMismatches[0]).toMatchObject({ shadow: 'nuevo texto', real: 'viejo texto' });
+  });
+});