chore(traceability): shift this branch's ids clear of master's

Master allocated DR-224 and UT-211 while this branch was in flight — the third
collision on this work. Everything here moves up by one: DR-224..236 become
DR-225..237, UT-211..213 become UT-212..214. UR-079, UR-080 and IR-033 were
still free and are unchanged.

Mechanical, and matched on each row's own text rather than on its number, so a
row cannot be shifted twice or the wrong one caught. Master's DR-224 (the
background-audio toggle) and UT-211 are untouched.

docs/architecture/03-data-flow.md

@@ -134,7 +134,7 @@ sequenceDiagram
 
 ## Video Stream Selection Flow
 
-**TRACES: UR-070, UR-079 | DR-224, DR-226, DR-227**
+**TRACES: UR-070, UR-079 | DR-225, DR-227, DR-228**
 
 Before a video plays, Rust decides *what stream* — direct play, remux or
 transcode, over which transport — and hands the player one self-describing