feat(profiler/behave_shell): G.5 emotional_valence.valence

Soft primitive — pure ratio over G.0 lexical counters:

* positive — positive_lex_hits > negative + obscenity, ≥ VALENCE_MIN_HITS
* negative — (negative + obscenity) > positive, sum ≥ VALENCE_MIN_HITS
* neutral  — fall-through

Skip below VALENCE_MIN_TYPED_CHARS (80). Confidence hard-capped at
EMOTIONAL_VALENCE_CONFIDENCE_CAP (0.5) inside the feature function;
0.30 below VALENCE_FULL_CONFIDENCE_MIN (200). Cap is registry
convention.

decnet/profiler/behave_shell/_features/__init__.py

@@ -24,6 +24,9 @@ from decnet.profiler.behave_shell._features.cognitive import (
     inter_command_consistency,
     inter_command_latency_class,
 )
+from decnet.profiler.behave_shell._features.emotional_valence import (
+    valence,
+)
 from decnet.profiler.behave_shell._features.environmental import (
     keyboard_layout,
     locale,
@@ -91,4 +94,5 @@ FEATURES: tuple[FeatureFn, ...] = (
     opsec_discipline,
     cleanup_behavior,
     multi_actor_indicators,
+    valence,
 )