fix: sync streamline self username cache convergence

internal/rpc/updates_delivery.go

@@ -2,6 +2,7 @@ package rpc
 
 import (
 	"context"
+	"strconv"
 	"time"
 
 	"go.uber.org/zap"
@@ -202,7 +203,7 @@ func (r *Router) registerUpdatesDeliveryPlan(ctx context.Context, plan *updatesD
 //  1. commit the exact account cursor carried by the delivered result;
 //  2. the just-delivered difference may retire its projected secret-chat events;
 //  3. membership routing is rebuilt before SetReceivesUpdates starts FIFO flush;
-//  4. the current session receives one complete self profile after becoming ready;
+//  4. one claim owner activates the session and emits its username convergence update;
 //  5. bootstrap jobs are published last, so they queue behind older pending updates.
 //
 // Each phase gets an independent timeout so one failed side effect cannot starve
@@ -236,15 +237,53 @@ func (r *Router) runUpdatesDeliveryPlan(plan updatesDeliveryPlan) {
 		}
 	}
 	if plan.markSessionReady {
-		ctx, cancel := context.WithTimeout(baseCtx, updatesDeliveryPhaseTimeout)
-		r.markSessionReceivesUpdatesNow(ctx, plan.readyUserID)
-		cancel()
-
-		ctx, cancel = context.WithTimeout(baseCtx, updatesDeliveryPhaseTimeout)
-		r.pushUpdatesReadySelfProfile(ctx, plan.readyUserID)
-		cancel()
+		r.activateSessionUpdates(baseCtx, plan.readyUserID)
 	}
 	if plan.publishBootstrap {
 		r.publishBootstrapAfterBaseline(baseCtx, plan.bootstrapUserID)
 	}
 }
+
+func (r *Router) activateSessionUpdates(baseCtx context.Context, userID int64) {
+	rawAuthKeyID, okRaw := RawAuthKeyIDFrom(baseCtx)
+	sessionID, okSession := SessionIDFrom(baseCtx)
+	if userID == 0 {
+		return
+	}
+	if !okRaw || !okSession {
+		// Direct handler tests and lightweight embeddings may not carry the full
+		// physical identity. They cannot benefit from a cross-request claim, but
+		// must retain the historical delivery-gated activation behavior.
+		ctx, cancel := context.WithTimeout(baseCtx, updatesDeliveryPhaseTimeout)
+		started := r.markSessionReceivesUpdatesNow(ctx, userID)
+		cancel()
+		if started {
+			ctx, cancel = context.WithTimeout(baseCtx, updatesDeliveryPhaseTimeout)
+			r.pushUpdatesReadySelfProfile(ctx, userID)
+			cancel()
+		}
+		return
+	}
+	if r.sessionUpdatesActivationStarted(baseCtx) {
+		return
+	}
+	key := string(rawAuthKeyID[:]) + strconv.FormatInt(sessionID, 10)
+	_, _, _ = r.updatesReadySF.Do(key, func() (any, error) {
+		// A callback may have been staged before another callback completed the
+		// same activation. Re-check under singleflight before touching storage.
+		if r.sessionUpdatesActivationStarted(baseCtx) {
+			return nil, nil
+		}
+		ctx, cancel := context.WithTimeout(baseCtx, updatesDeliveryPhaseTimeout)
+		started := r.markSessionReceivesUpdatesNow(ctx, userID)
+		cancel()
+		if !started {
+			return nil, nil
+		}
+
+		ctx, cancel = context.WithTimeout(baseCtx, updatesDeliveryPhaseTimeout)
+		r.pushUpdatesReadySelfProfile(ctx, userID)
+		cancel()
+		return nil, nil
+	})
+}