spike(semif): SemIf as Cicada's mood source is slower and less apt (no service change)

Against talk /face's guided pose (first paragraph 246 ms median), SemIf in
parallel adds 32 ms and SemIf-first adds 94 ms (n=72 each, noise floor 16.5 ms).
Removing the pose header saves only ~31 ms, and SemIf shares GPU 1 with the LLM.
Acceptable pose 67% vs 92% on clear-emotion lines, and the mood carried through
mundane follow-ups 7/15 vs 14/15. SemIf gestures far less (13% vs 58%).

README: rotations cost options^2 in suffix tokens, and /decide/shared returns
422 when an object state's last value ends in ) ; or }.

stacks/semif/README.md

@@ -46,6 +46,19 @@ curl -s -H "Authorization: Bearer $T" http://10.251.50.54:8032/decide -d '{
   calibration is not available together with `orderings` yet (422).
 - Past `MAX_QUEUE` (32) requests in progress, new POSTs get `429 busy` before their
   body is read.
+- ⚠ **Rotations cost options², not options.** The options live in each row's suffix, and
+  the shared prefix is only the state. So `rotations` over n options sends n rows each
+  carrying all n options. Measured 2026-09-27 on a short state, over 16 options of about
+  40 tokens each: **850 ms with rotations against 109 ms for one ordering** (10,304 against
+  644 suffix tokens, 5 calls after warm-up). One cold call at that size returned 503. The
+  VRAM table below covers binary decisions only. For many options, use one ordering or
+  shorter option text.
+- ⚠ **`/decide/shared` refuses some object states.** If the state is an object whose
+  LAST value ends in `)`, `;` or `}`, the service returns 422 "The fixed state prefix
+  does not match every full prompt". The closing `"}` merges with that character into one
+  token. The same text as a plain string state works, and `.`, `!`, `?`, `]`, `…` and
+  `—` endings work. Not fixed yet. Callers that pass user text last should
+  append a full stop or send a string state.
 
 ## ⚠ Probabilities are uncalibrated