feat(engagement): the in-app channel, core and web (engagement Phase 7)

ENGAGEMENT.md Phase 7. `user_notifications`, the in-app DeliveryChannel, the
four inbox routes, and the web surface — plus the two pieces earlier phases
assigned here that Phase 7's own acceptance line omits.

Four decisions settled by the org lead before any code:

1. `inapp` defaults to `instant` — the only channel that does. Push wakes a
   device somebody is holding and email leaves the building, so both are asked
   for; an inbox item is a row on a page the user chose to open. Left `off` the
   channel ships dead.
2. The phase takes push's `deliver` (§2603) and the web per-channel preferences
   screen (Phase 3's as-built), neither of which its own bullets mention.
3. The inbox takes `/auth/me/notifications` and `/account/notifications`; the
   preferences screen moves to `…/settings`. The plain word belongs to the
   content, which is what the bell opens.
4. `ctx.inbox.push` honours the user's in-app preference when `triggerId` names
   a registered trigger, and writes when it does not.

Server
- `user_notifications` + `model/userNotifications/`. The dedupe UNIQUE is scoped
  to the USER, narrower than the outbox's `(rule, user, channel)`: an inbox has
  no channel dimension, so two rows for one event would be one item shown twice.
- `engagement/inappChannel.js` — renders by block ROLE (first heading → title,
  first button → url, the rest → body) and inserts. `pushChannel.js` — a
  content-free `{stream, ref}` tickle whose ref deep-links the inbox row.
- `engine.liveChannels` orders `inapp` first (`CHANNEL_ORDER`) so that ref
  resolves on the first sweep. An ordering, not a dependency.
- `templates.renderInappByKey` + `resolveTemplate` extracted from `renderByKey`,
  so both channels take the same fallback chain.
- `inapp.event` seed → seedVersion 2: it named `body`/`url`, which nothing
  supplies. Renamed to the structural vocabulary the projection fills in.
- `utils/userNotificationsPrune.js` — nightly, READ items only, horizon in
  `settings.user_notifications_retain_days` (default 90).
- `GET /auth/me/notifications`, `…/unread-count`, `POST …/:id/read`,
  `POST …/read-all`. Swagger + route manifest + four component schemas.

Web
- `NotificationBell` in all three headers, polling its badge once a minute and
  pausing while the tab is hidden. `PlayerInbox` at `/account/notifications`.
- The preferences screen becomes a channel matrix over
  `/auth/me/notifications/channels` — a strict superset of the push-only stream
  list it replaces. The two legacy endpoints are untouched, so the shipped
  Android app keeps its wire shape.
- Staff get the same two screens at `/admin/notifications…`: `RequirePlayer`
  keeps them out of `/account`, so without this the inbox was unreachable for
  every non-player account. `lib/notificationPaths.js` is the one mapping.

Verified: 28 new server tests (5 of them against a real MariaDB, for the three
index/statement properties that are a server contract rather than a reading of
this code) + 3 client. Server suite green, client 327 green. A live rig walked
the whole path: two rules on one event produced three outbox rows and exactly
one inbox item, the tickle carried `ref: notification:2`, and the retention
sweep dropped an aged read row while keeping an equally aged unread one.

Docs: RunicGateway/docs#TBD, RunicGateway/runicgateway.com#TBD

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

server/src/engagement/templateSeeds.js

@@ -260,19 +260,33 @@ const SEEDS = [
     name: 'On-site notification',
     channel: 'inapp',
     protected: false,
-    seedVersion: 1,
+    // **seedVersion 2, and the bump is a correction rather than an improvement.**
+    // Phase 5a wrote this template before the channel that renders it existed, and
+    // named its variables `body` and `url` — names NOTHING supplies. A trigger
+    // declares domain names (`teamName`, `threadTitle`), and `projection.project`
+    // fills the gaps with the STRUCTURAL ones the generic seeds use: `title`,
+    // `intro`, `actionUrl`. So every rendering of this template would have found
+    // `body` and `url` missing and produced a title and nothing else. Renamed to
+    // the vocabulary `notify.event` uses, which is the same property stated once:
+    // a new trigger must render with no authoring at all.
+    seedVersion: 2,
     // No subject: an inbox row has a title, and the title is a block. The column
     // is email's, and leaving it NULL is how a non-email template says so.
     subject: null,
     variables: [
       { name: 'title', type: 'string', required: true, example: 'Your house is close to collapsing' },
-      { name: 'body', type: 'string', required: false, example: 'The Silver Anvil in Britain has entered its final decay stage.' },
-      { name: 'url', type: 'string', required: false, example: 'https://example.com/houses' },
+      { name: 'intro', type: 'string', required: false, example: 'The Silver Anvil in Britain has entered its final decay stage.' },
+      { name: 'actionUrl', type: 'string', required: false, example: '/player/uo/houses' },
     ],
+    // The three blocks map onto the three columns of `user_notifications` by ROLE
+    // (templates.js `renderInappByKey`): the heading is the item's title, the
+    // button is its one action, and everything else is the body. There is no
+    // unsubscribe line — an inbox item has nowhere to send someone that the
+    // preferences screen it links to from does not already reach.
     blocks: [
       heading('h', '{{title}}', 'h3'),
-      text('body', '{{body}}'),
-      button('cta', 'Open', '{{url}}'),
+      text('intro', '{{intro}}'),
+      button('cta', 'Open', '{{actionUrl}}'),
     ],
   },
 ]