Group voice and video calls with MatrixRTC and LiveKit

Every call in the web client now goes through MatrixRTC with a LiveKit
SFU, the model Element Call and Element X use; the legacy 1:1 m.call.*
calls are gone. In a room of two the other person is rung and can answer
or decline; in a bigger room a banner offers to join the call. Calls show
a grid of participant tiles with mute, camera, screen sharing and leave,
and media is end-to-end encrypted in encrypted rooms.

Server:
- MSC4140 delayed events (send/state with a delay, plus the
  delayed_events list/restart/cancel/send API), stored and scheduled, so
  a member whose client drops off is taken out of the call.
- POST /user/{userId}/openid/request_token, which lk-jwt-service uses to
  hand out LiveKit tokens.
- org.matrix.msc4143.rtc_foci in /.well-known/matrix/client, configured
  under client_api.rtc.
- Room presets let members send call membership state.
- Migration 0014 for both SQL dialects.

Deploy: LiveKit and lk-jwt-service in compose (calls.yml) and the helm
chart. Docs: docs/calls.md, configuration and deployment.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/internal/storage/sqlstore/sqlstore.go

@@ -69,6 +69,8 @@ type Store struct {
 	push     *Push
 	admin    *Admin
 	apps     *AppServices
+	delayed  *DelayedEvents
+	openID   *OpenIDTokens
 }
 
 // New builds a Store. It does not touch the database.
@@ -93,6 +95,8 @@ func New(opts Options) (*Store, error) {
 		push:     NewPush(opts.DB, opts.Rebind),
 		admin:    NewAdmin(opts.DB, opts.Rebind, opts.IsUniqueViolation),
 		apps:     NewAppServices(opts.DB, opts.Rebind),
+		delayed:  NewDelayedEvents(opts.DB, opts.Rebind),
+		openID:   NewOpenIDTokens(opts.DB, opts.Rebind),
 	}, nil
 }
 
@@ -138,6 +142,12 @@ func (s *Store) Admin() storage.AdminStore { return s.admin }
 // AppServices implements storage.Database.
 func (s *Store) AppServices() storage.AppServiceStore { return s.apps }
 
+// DelayedEvents implements storage.Database.
+func (s *Store) DelayedEvents() storage.DelayedEventStore { return s.delayed }
+
+// OpenIDTokens implements storage.Database.
+func (s *Store) OpenIDTokens() storage.OpenIDTokenStore { return s.openID }
+
 // Migrate implements storage.Database.
 func (s *Store) Migrate(ctx context.Context) error {
 	ms, err := s.migrations()