mail transport is configured in the app, not in .env

MAIL_TRANSPORT was a fallback left from the old registration flow that sent
confirmation mail. That flow is gone; the variable outlived it.

It was never the primary source anyway. getTransport reads server_config
('server-settings' → smtp) first, which already backs a full UI at Settings →
Server → SMTP and its API in api/server-settings/smtp.ts, supporting resend,
smtp and mailhog. The env var only answered when that was absent — which is a
second source of truth for something the owner can already set, with the failure
mode that a stale URL in .env silently answers for a server whose settings row
is simply empty.

Removed from transport.ts, .env.example and the setup script's Environment
section, which no longer asks for it. setup-old/ still mentions it; that is the
archive and is left alone.

Also split the try. It wrapped the read AND the transport construction and
swallowed both, so three different problems produced one message. Unreachable
database, nothing configured, and stored settings that do not build a transport
now say different things, because the fix for each is different and this message
is all the caller ever sees.

The two consumers — queue/engine.ts and auth/forgot-password.ts — now raise
until SMTP is set in the UI, which is the honest answer rather than a regression.

Not typechecked: node_modules is empty here and installs are frozen. transport.ts
parses under `bun build --no-bundle`; the setup script was run and no longer
prompts for or writes the variable.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/setup/officer-setup.sh

@@ -464,7 +464,6 @@ if ! skip; then
   ENV_VAULT_STORE_KEY="$(env_get VAULT_STORE_KEY)"
   ENV_PORT="$(env_get PORT)"
   ENV_PUBLIC_URL="$(env_get PUBLIC_URL)"
-  ENV_MAIL_TRANSPORT="$(env_get MAIL_TRANSPORT)"
   ENV_DISCORD_WEBHOOK="$(env_get DISCORD_BUG_REPORT_WEBHOOK)"
   ENV_BROWSER_RELAY_PORT="$(env_get BROWSER_RELAY_PORT)"
 
@@ -522,11 +521,6 @@ if ! skip; then
   echo ""
   echo "     ALLOW_ANY_ORIGIN=${ENV_ALLOW_ANY_ORIGIN} — ${ORIGIN_WHY}"
 
-  echo ""
-  ENV_MAIL_TRANSPORT="${ENV_MAIL_TRANSPORT:-}"
-  read -rp "  Mail transport, blank for none [${ENV_MAIL_TRANSPORT}]: " REPLY_MAIL || true
-  ENV_MAIL_TRANSPORT="${REPLY_MAIL:-$ENV_MAIL_TRANSPORT}"
-
   echo ""
   echo "     to write:"
   echo "       PORT=${ENV_PORT}   BROWSER_RELAY_PORT=${ENV_BROWSER_RELAY_PORT}"

scripts/setup/officer-setup/lib/env.sh

@@ -111,7 +111,6 @@ HOME_DIR="${USER_HOME}"
 # tailnet; written explicitly here so the machine's actual situation decides it.
 ALLOW_ANY_ORIGIN="${ENV_ALLOW_ANY_ORIGIN}"
 
-MAIL_TRANSPORT="${ENV_MAIL_TRANSPORT}"
 DISCORD_BUG_REPORT_WEBHOOK="${ENV_DISCORD_WEBHOOK}"
 ENVF