release: 0.1.0: Phases 0-11: panel, Postfix/DKIM, milter, backup, Docker image

Initial feature-complete implementation of the v1.0 specification (phases 0-11 of `docs/implementation-plan.md`).
Added:
  - Panel (Go, single static binary) with SQLite persistence, one-time
  - Domain management with per-domain DKIM (RSA-2048, generated in pure Go) and
  - Application (sender identity) management: SASL credentials via `sasldb2`,
  - Full Postfix relay config generated from env at container start: SMTPS 465,
  - Journal milter (pure Go, `go-milter`) recording every send to `send_log`;
  … (6 more in CHANGELOG)

Full detail: CHANGELOG.md (0.1.0).

deploy/.env.example

@@ -0,0 +1,31 @@
+# Copy to .env next to docker-compose.yml and fill in.
+
+# Required — the container refuses to start without it. Hostname used both for
+# the panel's TLS vhost and for Postfix's SASL realm (SASL_REALM defaults to
+# this) and myhostname; must also match your PTR record. Must match the
+# certificate your reverse proxy obtains. Bare FQDN only — no scheme or port.
+SELFPOST_HOSTNAME=mail.example.com
+
+# Set to true to also enable RFC 6409 submission (587/STARTTLS) alongside the
+# primary 465/smtps listener.
+SUBMISSION_ENABLE=false
+
+# Level-1 backstop rate limit (anvil) — see README "Rate limiting".
+RATE_LIMIT_MESSAGES_PER_IP=100
+RATE_LIMIT_WINDOW_SECONDS=3600
+
+# Days of send-log history kept before the background sweep deletes rows.
+SEND_LOG_RETENTION_DAYS=90
+
+# Sliding idle timeout for the panel login session, in days. No absolute cap:
+# an admin who keeps coming back stays signed in indefinitely. Polling by the
+# monitoring screens does not count as activity, only navigation/actions do.
+PANEL_SESSION_IDLE_DAYS=7
+
+# Comma-separated CIDRs (bare IPs allowed) of reverse proxies allowed to
+# supply X-Forwarded-For for login/setup rate-limiting. Leave unset unless
+# you know the exact address of your reverse proxy — trusting the wrong
+# source lets a client spoof its rate-limit key. Behind the default Apache
+# host-network setup this is typically the Docker bridge gateway, e.g.
+# TRUSTED_PROXY_CIDR=172.18.0.1
+