feat(realism): LLM enrichment for user-class file bodies

Stage 6 of the realism migration. User-class file bodies (note,
todo, draft, script) optionally get LLM-authored content; system
classes (cron / daemon logs, /tmp caches) stay template-only because
formulaic *is* the right look for them.

New surface:

- realism.llm.circuit.LLMCircuitBreaker — process-local sliding-window
  breaker. 3 consecutive failures trip open; 60s cooldown to half-open;
  half-open success closes, failure re-opens. Protects the orchestrator
  tick from sustained Ollama wedges (per-call timeout already covers
  one-shot hangs).
- realism.prompts._style — em-dash suppression lifted from the
  email prompt. Persona.uses_llms_heavily opts out per the
  feedback_em_dash_llm_tell.md memory. Includes strip_em_dashes
  belt-and-braces sub for output that slipped past the prompt rule.
- realism.prompts.filebody — class-conditioned prompts (note / todo
  / draft / script) with persona context, language pinning, output
  shape rule.
- realism.bodies.make_body_with_llm — async wrapper around make_body
  that calls the LLM when one is provided AND the breaker allows.
  Falls back to template on timeout / error / empty / system-class.

Wiring:

- scheduler.pick_file accepts optional llm + llm_breaker + llm_timeout.
  When the planner picks a create action and the content_class is a
  user-class, the body_hint is replaced with the LLM-authored body
  (or falls back to the deterministic body_hint).
- orchestrator.worker constructs get_llm() at startup gated by
  DECNET_REALISM_LLM env var (any non-empty value enables; empty /
  "off" / "none" / "0" disables). Passes llm + breaker through every
  tick.
- decnet orchestrate gains --llm/--no-llm flag overriding the env var.

decnet/orchestrator/scheduler.py

@@ -121,6 +121,9 @@ async def pick_file(
     *,
     now: Optional[datetime] = None,
     rand: Optional[secrets.SystemRandom] = None,
+    llm: Any = None,
+    llm_breaker: Any = None,
+    llm_timeout: float = 60.0,
 ) -> Optional[Action]:
     """Realism-driven file action — create or edit.
 
@@ -179,17 +182,46 @@ async def pick_file(
             synthetic_file_uuid=(edit_candidate or {}).get("uuid", ""),
             mtime=plan.mtime,
         )
+
+    # Create branch.  If LLM is wired, optionally swap body_hint for
+    # an LLM-authored body.  Always keep the deterministic body_hint
+    # as the fallback the function call returns when LLM
+    # times out / errors / breaker-trips.
+    body = plan.body_hint or ""
+    if llm is not None and plan.content_class.is_user_class():
+        persona_obj = _persona_by_name(enriched, plan.persona)
+        if persona_obj is not None:
+            from decnet.realism.bodies import make_body_with_llm
+            body = await make_body_with_llm(
+                plan.content_class,
+                persona_obj,
+                llm=llm,
+                breaker=llm_breaker,
+                timeout=llm_timeout,
+                rand=rng,
+            )
     return FileAction(
         dst_uuid=plan.decky_uuid,
         dst_name=plan.decky_name,
         path=plan.target_path,
-        content=plan.body_hint or "",
+        content=body,
         persona=plan.persona,
         content_class=plan.content_class.value,
         mtime=plan.mtime,
     )
 
 
+def _persona_by_name(
+    enriched: list[dict[str, Any]], name: str,
+) -> Optional[EmailPersona]:
+    """Find the persona instance the planner used; ``None`` if missing."""
+    for decky in enriched:
+        for persona in decky.get("_realism_personas") or []:
+            if persona.name == name:
+                return persona
+    return None
+
+
 async def _resolve_personas(
     deckies: Sequence[dict[str, Any]],
     repo: Any,