feat(push): M7 backend — opt-in push notifications via self-hosted ntfy

Additive, v1-only backend contract for the Android app's opt-in push (Part 1 of
M7; docs/android/PLAN.md §11). The app is a pure consumer — this lands the
endpoints, fan-out, and relay it needs.

- Schema: push_devices (per-device endpoint) + notification_subscriptions
  (per-user opted-in streams), FK→users ON DELETE CASCADE.
- Stream catalog + event→stream mapping (config/notificationStreams.js): public
  streams (news.post, server.status, idoc.warning, champ.start, governor.election)
  drawn ONLY from the SSE PUBLIC_KINDS allowlist; personal owner-keyed streams
  (vendor.sale, house.idoc, account.login). Full-state upserts (champ/city) fire
  only on a real transition via an injectable tracker.
- Fan-out (utils/pushDispatch.js): content-free tickles ({ stream, ref }) POSTed
  to each subscribed device; never throws. Two producers — shardIngest.ingest
  (beside the SSE broadcast) and the create/publish-post path (news.post).
  Personal events resolve to the owner via shardLinks. SSRF guard: endpoints must
  be HTTPS, non-private, and on the NTFY_BASE_URL/NTFY_ALLOWED_ORIGINS allow-set —
  enforced at registration and every publish.
- Routes under the role-agnostic self surface (never /admin): POST|GET
  /auth/me/devices, DELETE /auth/me/devices/:id, GET
  /auth/me/notifications/streams, GET|PUT /auth/me/notifications/subscriptions.
  Swagger regenerated (4 paths, PushDevice/NotificationStreams/etc. schemas).
- ntfy service in docker-compose.yml: pinned image, declarative ./ntfy/server.yml,
  no published host port, anonymous unguessable topics (no accounts) — zero
  interactive setup. No publish token required (content-free design); optional
  NTFY_PUBLISH_TOKEN honored.
- Tests: pushDispatch (mapping, PUBLIC_KINDS gate, owner-keying, SSRF guard,
  content-free payload) + notifications route auth gate. Full suite green (247).

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

server/src/utils/shardIngest.js

@@ -17,6 +17,7 @@ const shardStateModel = require('../model/shardState/shardState.model')
 const shardLinksModel = require('../model/shardLinks/shardLinks.model')
 const uoLinkConfigModel = require('../model/uoLinkConfig/uoLinkConfig.model')
 const broadcaster = require('./shardBroadcast')
+const pushDispatch = require('./pushDispatch')
 const defaultLog = require('./logger')('shard-ingest')
 
 // Notable kinds appended to the shard_events log. High-frequency/session kinds
@@ -194,6 +195,7 @@ async function ingest(event, deps = {}) {
     shardLinks: deps.shardLinks || shardLinksModel,
     uoLinkConfig: deps.uoLinkConfig || uoLinkConfigModel,
     broadcast: deps.broadcast || broadcaster.broadcast,
+    pushDispatch: deps.pushDispatch || pushDispatch.fromShardEvent,
     log: deps.log || defaultLog,
   }
 
@@ -226,6 +228,12 @@ async function ingest(event, deps = {}) {
     } catch (err) {
       d.log.warn('broadcast failed', { kind: event.kind, message: err.message })
     }
+    // Opt-in push fan-out, off the same event source as the SSE broadcast.
+    // Fire-and-forget (a slow/dead ntfy relay must never delay or fail ingest);
+    // fromShardEvent is self-guarding, but .catch() covers any lookup rejection.
+    Promise.resolve(d.pushDispatch(event, { shardLinks: d.shardLinks })).catch((err) =>
+      d.log.warn('push dispatch failed', { kind: event.kind, message: err.message }),
+    )
   }
 
   return { logged, stored }