Phase 5: reply drafts — template/LLM draft, edit, SMTP send (AUD-71)

Implements Phase 5 of AGENTS.md §11 (FR-8, FR-15):

- Message detail pane (GET /partials/message) with body, recommended
  action, reply identity, template picker, editable draft, and history.
- internal/reply: OmniRoute (OpenAI-compatible) chat client and a
  template-based draft generator. All non-JEV models go through
  OmniRoute (§10).
- internal/mailops: SMTP send over smtp.gmail.com:587 with STARTTLS and
  the app password, forcing IPv4 (§9); FR-15 reply identity (send as the
  arrived-at X-Pm-Original-To address, else "Sam Rolfe"); threading via
  In-Reply-To/References; -check-smtp safe verification; and a
  [Gmail]/Sent Mail thread check.
- Migration v5 stores messages.message_id_header and drafts.sent_at;
  mailfetch parses Message-ID.
- Send is user-triggered only: CSRF + UI confirm + confirm=yes guard,
  no auto-send, duplicate-send refused. A sent reply files the original
  under Replied-to/<address> and logs every step (FR-13).
- Tests for reply, mailops SMTP/identity/thread check, store drafts and
  migration v5, and the server draft/edit/send guards.
- docs/phase5-replies.md, README, .env.example, docker-compose updated.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.env.example

@@ -30,6 +30,11 @@ EMAIL_AGENT_IMAP_PORT=993
 EMAIL_AGENT_IMAP_LOOKBACK_DAYS=14
 EMAIL_AGENT_IMAP_MAX_MESSAGES=100
 
+# --- Gmail SMTP (Phase 5 replies) -------------------------------------------
+# Submission uses STARTTLS on 587 and forces IPv4, like IMAP.
+EMAIL_AGENT_SMTP_HOST=smtp.gmail.com
+EMAIL_AGENT_SMTP_PORT=587
+
 # --- Integrations (used from later phases) ---------------------------------
 # JEV is the TypeSafe System One HTTP API. JEV_BASE_URL defaults to the
 # documented host https://api.typesafe.ai when unset.
@@ -39,6 +44,9 @@ JEV_MODEL=jev-latest
 # Classifier bounds (FR-3): in-flight JEV requests, and messages per run.
 EMAIL_AGENT_CLASSIFY_CONCURRENCY=4
 EMAIL_AGENT_CLASSIFY_MAX_MESSAGES=200
+# OmniRoute is the house AI gateway; all non-JEV models go through it. The
+# default base URL is the gateway on .13 (http://192.168.20.13:20129/v1).
 OMNIROUTE_BASE_URL=
 OMNIROUTE_API_KEY=
+OMNIROUTE_MODEL=auto/best-chat
 HUB_TOKEN=