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/cli/orchestrator.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Optional
+
 import typer
 
 from . import utils as _utils
@@ -17,8 +19,16 @@ def register(app: typer.Typer) -> None:
             False, "--daemon", "-d",
             help="Detach to background as a daemon process",
         ),
+        llm: Optional[bool] = typer.Option(
+            None, "--llm/--no-llm",
+            help=(
+                "Enable / disable LLM enrichment of user-class file "
+                "bodies.  Default reads $DECNET_REALISM_LLM (any "
+                "non-empty value enables; 'off' / unset disables)."
+            ),
+        ),
     ) -> None:
-        """Inject synthetic life (inter-decky traffic + file ops) into the fleet."""
+        """Inject synthetic life (inter-decky traffic + file ops + email) into the fleet."""
         import asyncio
         from decnet.orchestrator import orchestrator_worker
         from decnet.web.dependencies import repo
@@ -27,14 +37,17 @@ def register(app: typer.Typer) -> None:
             log.info("orchestrator daemonizing interval=%d", interval)
             _utils._daemonize()
 
-        log.info("orchestrator starting interval=%d", interval)
+        log.info(
+            "orchestrator starting interval=%d llm=%s",
+            interval, "default" if llm is None else ("on" if llm else "off"),
+        )
         console.print(
             f"[bold cyan]Orchestrator starting[/] (interval: {interval}s)"
         )
 
         async def _run() -> None:
             await repo.initialize()
-            await orchestrator_worker(repo, interval=interval)
+            await orchestrator_worker(repo, interval=interval, llm_enabled=llm)
 
         try:
             asyncio.run(_run())