feat(setup): Stage 1 first-time setup wizard backend (no UI)

Task #534 — backend, infra, tooling. UI ships in Stage 2 (#535).

Backend
- New system_settings table (id=1 singleton): installed flag, base_url,
  local_domain, local_ip, https_mode, app_version. Pushed to dev DB.
- New /api/setup/status (open) and /api/setup/{validate,complete}
  (gated by requireSetupOpen — 409 once installed).
- completeInstall is fully transactional: pg_advisory_xact_lock
  serializes concurrent callers, double-gates on installed flag and
  admin existence, then atomically creates the admin user, assigns
  admin role + Admins/Everyone groups, and flips system_settings to
  installed=true. Rolls back on any failure.
- Added redirectIfSetupNeeded() helper returning the full SetupStatus
  payload alongside a redirect target for SPA routing decisions.
- Zod validation, bcrypt hashing, in-memory rate limiter on the
  setup endpoints.

Backward compat
- scripts/src/seed.ts now branches on installed flag + admin
  existence + SEED_*_PASSWORD env vars. Legacy installs (admin
  exists, system_settings empty) get backfilled to installed=true
  via ON CONFLICT DO UPDATE so they are never forced through the
  wizard. When env passwords are unset and no admin exists, the
  seed prints a wizard hint instead of seeding.

Infra
- docker-compose.yml: replaced nginx edge with a Caddy service that
  mounts ./certs and ./docker/Caddyfile{,.skip}. The web service no
  longer publishes a port directly — Caddy is the only public ingress.
- Caddy entrypoint picks Caddyfile.skip (HTTP-only, no certs) when
  HTTPS_MODE=skip so a fresh host without mkcert can still boot.
- docker/Caddyfile: HTTPS site for LOCAL_DOMAIN/LOCAL_IP with
  WebSocket upgrade preserved and an HTTP→HTTPS redirect.
- start.sh: preserved. Now auto-picks HTTPS_MODE=skip when no cert
  is on disk and maps Caddy's HTTP_PORT to APP_PORT in skip mode so
  the legacy http://localhost:${APP_PORT} URL keeps working. In
  local/byo mode it prints the https://${LOCAL_DOMAIN} URL.
- .env.example: added LOCAL_DOMAIN, LOCAL_IP, BASE_URL, HTTP_PORT,
  HTTPS_PORT, HTTPS_MODE; SEED_*_PASSWORD now optional.

Tooling
- scripts/local-setup.sh: idempotent OS-aware bootstrap (.env upsert,
  mkcert hint, cert SAN check, dry-run via LOCAL_SETUP_DRY_RUN).

Tests
- artifacts/api-server/tests/setup-wizard.test.mjs: 7/7 pass.
- scripts/tests/local-setup.test.mjs: 2/2 pass.

Constraints honored: no force-push, no destructive ops, start.sh
preserved & still works, scripts idempotent, volumes/DB never
touched, HTTPS skip mode dev-only, wizard does not edit
LOCAL_DOMAIN/LOCAL_IP.

Out of scope / not addressed: pre-existing TS errors in
routes/users.ts and pre-existing failure in
executive-meetings-postpone-race.test.mjs.

artifacts/api-server/src/middlewares/setupGate.ts

@@ -4,6 +4,14 @@ import { isSetupOpen } from "../lib/setupService";
 // Blocks /api/setup/{validate,complete} once the system is installed.
 // /api/setup/status is intentionally NOT guarded — the SPA must always
 // be able to read install state to decide its routing.
+//
+// Gate semantics: "open" means BOTH system_settings.installed=false AND
+// no admin user exists. The admin-existence check is intentional belt-
+// and-braces — it protects legacy installs that pre-date the
+// system_settings table (where installed defaults to false until
+// backfilled by seed.ts). Without it, a fresh API container running
+// against a populated DB could let a second wizard run create another
+// first admin. Stricter than "installed=true only" by design.
 export async function requireSetupOpen(
   _req: Request,
   res: Response,

scripts/local-setup.sh

@@ -186,15 +186,19 @@ else
   log "Generating local certificate via mkcert ..."
   mkcert -cert-file "$CERT_FILE" -key-file "$KEY_FILE" \
     "$LOCAL_DOMAIN" localhost 127.0.0.1 "$LOCAL_IP"
-  if command -v mkcert >/dev/null 2>&1; then
-    CAROOT="$(mkcert -CAROOT 2>/dev/null || true)"
-    if [ -n "$CAROOT" ]; then
-      echo
-      echo "    Root CA stored in: $CAROOT"
-      echo "    To trust HTTPS on phones / other devices, install rootCA.pem"
-      echo "    from that directory."
-      echo
-    fi
+fi
+
+# Always print the mkcert root CA location so an operator running this
+# script (first time or repeat) can find rootCA.pem to install on
+# phones / other devices.
+if command -v mkcert >/dev/null 2>&1; then
+  CAROOT="$(mkcert -CAROOT 2>/dev/null || true)"
+  if [ -n "$CAROOT" ]; then
+    echo
+    echo "    Root CA stored in: $CAROOT"
+    echo "    To trust HTTPS on phones / other devices, install rootCA.pem"
+    echo "    from that directory."
+    echo
   fi
 fi
 

scripts/src/seed.ts

@@ -112,8 +112,19 @@ async function main() {
   const adminPassword = process.env.SEED_ADMIN_PASSWORD;
   const userPassword = process.env.SEED_USER_PASSWORD;
 
-  // Detect existing install state. The system_settings row may not exist
-  // yet on a brand-new DB; treat "no row" as installed=false.
+  // Ensure a single source-of-truth row in system_settings always
+  // exists at id=1. If absent (brand-new DB), insert installed=false
+  // so /api/setup/status, the wizard, and admin-panel reads all see
+  // a consistent shape from minute one. The completeInstall flow
+  // (and the legacy backfill below) flip this row to installed=true.
+  await db
+    .insert(systemSettingsTable)
+    .values({ id: 1, installed: false })
+    .onConflictDoNothing();
+
+  // Detect existing install state. After the bootstrap insert above
+  // the row always exists, so installed defaults to false until the
+  // wizard or backfill flips it.
   const sysRows = await db.select().from(systemSettingsTable).limit(1);
   const installedFlag = sysRows[0]?.installed ?? false;