feat: sync account deletion lifecycle

Sync telesrv 73f5c91 (feat(account): implement unified account deletion lifecycle).

Skipped telesrv docs changes per public sync rules.

internal/app/userprojection/deleted_test.go

@@ -0,0 +1,19 @@
+package userprojection
+
+import (
+	"context"
+	"testing"
+
+	"telesrv/internal/domain"
+)
+
+func TestDeletedUserProjectionCannotReintroducePII(t *testing.T) {
+	in := domain.User{ID: 42, AccessHash: 99, Deleted: true, Phone: "stale", FirstName: "Stale", PhotoID: 123, Contact: true}
+	got, err := New().One(context.Background(), 7, in)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !got.Deleted || got.ID != 42 || got.Phone != "" || got.FirstName != "" || got.PhotoID != 0 || got.Contact {
+		t.Fatalf("deleted projection leaked PII: %+v", got)
+	}
+}