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/web/db/models/__init__.py

@@ -58,6 +58,8 @@ from .health import (
     HealthResponse,
 )
 from .orchestrator import (
+    OrchestratorEmail,
+    OrchestratorEmailsResponse,
     OrchestratorEvent,
     OrchestratorEventsResponse,
 )
@@ -193,6 +195,8 @@ __all__ = [
     "ComponentHealth",
     "HealthResponse",
     # orchestrator
+    "OrchestratorEmail",
+    "OrchestratorEmailsResponse",
     "OrchestratorEvent",
     "OrchestratorEventsResponse",
     # logs