feat: missed-event fetch and notification fold-in (PUT-1681)

[Salazareo]

Stacked on DS/put-1679 — review only this PR's diff; merges bottom-up.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	93.8% ⬆️ +0.04%	27277 / 29077
🔵	Statements	91.89% ⬇️ -0.11%	29574 / 32184
🔵	Functions	90.16% ⬆️ +0.15%	4924 / 5461
🔵	Branches	80.71% ⬆️ +0.06%	19569 / 24245

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
src/backend/types.ts	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%
src/backend/clients/event/types.ts	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%	100% 🟰 ±0%
src/backend/controllers/events/EventsController.ts	85.36%	49.65%	66.66%	92.22%	6, 24-26, 32, 33, 34, 38-39, 44, 45, 47, 182-184, 190-192
src/backend/controllers/events/limits.ts	100%	100%	100%	100%
src/backend/services/events/EventsService.ts	87.85%	81.81%	90.95%	93.27%	626-629, 750, 768-771, 797-800, 806, 812, 825-828, 846, 905, 924, 932, 1003, 1027, 1035, 1043, 1054, 1084, 1086, 1105-1106, 1121, 1157, 1159, 1164, 1185, 1187, 1209, 1287, 1291-1292, 1308, 1313, 1347, 1350, 1424, 1429, 1456, 1458, 1462, 1469, 1528-1531, 1533-1536, 1541-1544, 1579, 1599, 1619-1623, 1655-1659, 1690, 1705, 1717, 1736, 1748, 1750, 1761, 1773, 1792, 1805, 1840-1841, 1867, 1875, 1900, 1923, 1925, 1930, 1940, 1951, 1957, 2040, 2065, 2077-2081, 2099-2100, 2118, 2163-2165, 2200, 2246, 2314, 2335, 2358, 2388, 2391, 2392, 2397, 2422, 2455, 2458, 2460, 2487, 2493, 2536, 2637, 2693, 2762, 2771, 2782, 2788, 2831-2832, 2918, 2924, 2967, 2973, 3009-3013, 3035, 3043, 3051, 3061, 3137-3140, 3200, 3277, 3337-3341, 3400, 3411-3416, 3513, 3536, 3550, 3564, 3609, 3612, 3622, 3635, 3648-3649, 3677, 3710, 3719-3720, 3817, 3866-3868, 3879-3886, 3896-3897, 3907-3908
src/backend/services/events/anchors.ts	91.66%	83.33%	100%	93.93%	147, 172-174, 226-228
src/backend/services/events/notifFetch.ts	95.65%	73.07%	100%	94.73%	83
src/backend/services/events/registry.ts	100%	91.66%	100%	100%
src/backend/services/events/subjects.ts	99.1%	96.42%	100%	100%	97
src/backend/services/notification/NotificationService.ts	92.92% ⬇️ -2.31%	90% ⬆️ +7.86%	80.76% ⬇️ -0.19%	92.94% ⬇️ -5.17%	41-44, 136, 208-210, 246-247
src/backend/services/notification/notificationSocket.ts	88%	80%	90%	95.23%	85, 104, 115
src/backend/stores/notification/NotificationStore.js	97.26% ⬇️ -2.74%	77.21% ⬇️ -3.43%	100% ⬆️ +7.70%	100% 🟰 ±0%	87, 197

Generated in workflow #944 for commit 6cce57b by the Vitest Coverage Report Action