feat(emailgen): Ollama-driven fake email worker for IMAP/POP3 deckies

Second orchestrator worker (decnet emailgen) that drips persona-driven,
threaded, multi-language fake emails into running mail deckies.  Personas
live on Topology.email_personas; topology-wide language_default falls
through to any persona that doesn't pin its own.  Em-dashes are
suppressed at the prompt layer by default and only lifted for personas
explicitly marked uses_llms_heavily — em-dashes are an LLM tell and a
flat corpus of em-dashed mail is a giveaway.

EML delivery writes into /var/spool/decnet-emails/<thread>/<msg>.eml on
the mail decky via docker exec; wiring the IMAP/POP3 templates to read
from that spool (replacing the hardcoded _BAIT_EMAILS) is the next step.

decnet/cli/__init__.py

@@ -24,6 +24,7 @@ from . import (
     bus,
     db,
     deploy,
+    emailgen,
     forwarder,
     geoip,
     init,
@@ -56,7 +57,7 @@ for _mod in (
     api, swarmctl, agent, updater, listener, forwarder,
     swarm,
     deploy, lifecycle, workers, inventory,
-    web, profiler, orchestrator, reconciler, sniffer, db,
+    web, profiler, orchestrator, emailgen, reconciler, sniffer, db,
     topology, bus, geoip, init, webhook,
 ):
     _mod.register(app)

decnet/cli/emailgen.py

@@ -0,0 +1,66 @@
+"""``decnet emailgen`` — second orchestrator worker.
+
+Sibling of :mod:`decnet.cli.orchestrator`.  Two distinct CLI entrypoints
+match the "workers are independent, never coupled" principle: a wedged
+ollama call in emailgen does not stall the SSH-flavoured orchestrator,
+and systemd supervises each loop separately.
+"""
+from __future__ import annotations
+
+import os
+
+import typer
+
+from . import utils as _utils
+from .utils import console, log
+
+
+def register(app: typer.Typer) -> None:
+    @app.command(name="emailgen")
+    def emailgen_cmd(
+        interval: int = typer.Option(
+            300, "--interval", "-i",
+            help="Seconds between fake-email generation ticks (default 5m)",
+        ),
+        daemon: bool = typer.Option(
+            False, "--daemon", "-d",
+            help="Detach to background as a daemon process",
+        ),
+        model: str = typer.Option(
+            "", "--model", "-m",
+            help="Ollama model override (defaults to $DECNET_EMAILGEN_MODEL "
+                 "or 'llama3.1')",
+        ),
+    ) -> None:
+        """Drip fake corporate emails into running IMAP/POP3 mail deckies."""
+        import asyncio
+        from decnet.orchestrator.emailgen import emailgen_worker
+        from decnet.web.dependencies import repo
+
+        if daemon:
+            log.info("emailgen daemonizing interval=%d", interval)
+            _utils._daemonize()
+
+        # Honour the env var when the flag was left empty so systemd unit
+        # files can configure the model centrally without per-host CLI
+        # tweaks.  Empty -> let the worker apply its own default.
+        resolved_model = model or os.environ.get("DECNET_EMAILGEN_MODEL", "")
+        log.info(
+            "emailgen starting interval=%d model=%s",
+            interval, resolved_model or "default",
+        )
+        console.print(
+            f"[bold cyan]Emailgen starting[/] (interval: {interval}s"
+            f"{', model: ' + resolved_model if resolved_model else ''})"
+        )
+
+        async def _run() -> None:
+            await repo.initialize()
+            await emailgen_worker(
+                repo, interval=interval, model=resolved_model or None,
+            )
+
+        try:
+            asyncio.run(_run())
+        except KeyboardInterrupt:
+            console.print("\n[yellow]Emailgen stopped.[/]")