feat(11-01): add the conga job framework on River with transactional dispatch

- Pin River v0.47.0 (riverdatabasesql, rivertype) and tidy the example modules
- lagoon.Migrate runs the summercms.conga set: River schema v7 and summer_jobs
  with the apparatus columns plus an internal river_job_id link
- conga.Manager.Dispatch writes the summer_jobs row (status IN_PROGRESS) and the
  River job on the caller's *sql.Tx; a rollback leaves neither
- conga.Job wraps typed job functions so plugins never import River
- conga.StartWorker runs one client on riverdatabasesql.NewWithPgxListener with
  a single-connection LISTEN pool; the final failed attempt sets ERROR
- TestListenPickupLatency: 30s poll, pickup under 1s; poll-only control 2s miss

README.md

@@ -88,6 +88,7 @@ The `migrate`, `migrate:status`, `migrate:rollback`, `serve` and admin commands
 | [bouncer](modules/bouncer/README.md) | Authentication for SummerCMS: HS256 JWT minting, verification and refresh, request guards, a revoked-token blacklist and bcrypt password helpers. |
 | [cabana](modules/cabana/README.md) | Schema-driven admin backend that compiles WinterCMS-style YAML list, form, filter and relation definitions at boot and serves them as a JSON admin API next to the embedded admin SPA. |
 | [compass](modules/compass/README.md) | Layered YAML configuration with per-environment directories, `SUMMER_` environment overrides, embedded plugin defaults and dot-path access. |
+| [conga](modules/conga/README.md) | Background jobs on River over the shared Postgres pool: transactional dispatch, a `summer_jobs` progress record, in-process or dedicated workers, and a wall-clock scheduler. |
 | [festival](modules/festival/README.md) | Typed, synchronous event bus with listener priorities, payload collection and stop-when-handled dispatch. |
 | [fetchguard](modules/fetchguard/README.md) | Guarded outbound HTTPS fetcher that blocks private and reserved addresses and enforces host, size and timeout limits. |
 | [lagoon](modules/lagoon/README.md) | Postgres data layer: the shared GORM connection, per-plugin migrations, model helpers and file attachments. |