Fix animations: stirrer/grains static at rest, fire uses power soll

- Stirrer starts at speed 0 (was 50) so blades don't spin on connect
- Grain particles only levitate when stirrer is running
- Fire size driven by PowerSet (soll) instead of Power (ist)
- Split animation-play-state out of stirrer shorthand for reliable pausing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JLR2133M2PyjiYq584i2G7

web/style.css

@@ -163,7 +163,9 @@ header#connection-bar {
 .grain-p {
   fill: #c8a060;
   animation: float-p var(--fp-dur, 3s) ease-in-out infinite var(--fp-del, 0s);
+  animation-play-state: paused;
 }
+#grain-particles.stirring .grain-p { animation-play-state: running; }
 #grain-particles { transition: opacity 0.5s; }
 
 /* Stirrer animation */
@@ -173,7 +175,8 @@ header#connection-bar {
 #stirrer-blades {
     transform-box: fill-box;
     transform-origin: 50% 50%;
-    animation: stir-rotate var(--stir-duration, 1s) linear infinite paused;
+    animation: stir-rotate var(--stir-duration, 1s) linear infinite;
+    animation-play-state: paused;
 }
 #stirrer-blades.spinning {
     animation-play-state: running;