R-1112: open the family store when the controller starts

Found on demo-hp with 0.325.0-rc.1: the store (and so the conversion of an old family.json) opened only on the
first family request; a box nobody visits through a family gate kept the session values. OpenFamilyStore from
main, one INFO line with the count. TestR1112_StartConvertsTheFamilyFile, TestR1112_MainOpensTheFamilyStore,
red-proved.

Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/r1111_r1113_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"log"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -17,6 +18,7 @@ import (
 
 	"golang.org/x/crypto/bcrypt"
 
+	"gitea.dooplex.hu/admin/felhom-controller/internal/config"
 	"gitea.dooplex.hu/admin/felhom-controller/internal/family"
 )
 
@@ -308,3 +310,32 @@ func TestR1113_HouseholdPassesLeaveOneSession(t *testing.T) {
 		t.Fatalf("after the older one expired: %d live household sessions, want 1", live)
 	}
 }
+
+// R-1112 at START: the conversion happens when the dashboard starts, not on the first family request (measured on demo-hp
+// 9201 with rc.1: up, family.json still in the old shape, because nobody had passed a family gate). OpenFamilyStore is
+// what main calls; the conversion is logged by count, never a value.
+// Red-proof: OpenFamilyStore with an empty body → the old values stay in the file and this fails.
+func TestR1112_StartConvertsTheFamilyFile(t *testing.T) {
+	dir := t.TempDir()
+	household := "0f1e2d3c4b5a69788796a5b4c3d2e1f00f1e2d3c4b5a6978"
+	exp := time.Now().Add(20 * 24 * time.Hour).UTC().Format(time.RFC3339)
+	path := filepath.Join(dir, "family.json")
+	if err := os.WriteFile(path, []byte(`{"members":[],"sessions":[{"id":"`+household+`","member":"","gen":0,"exp":"`+exp+`"}]}`), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	cfg := config.Default()
+	cfg.Paths.DataDir = dir
+	var logs strings.Builder
+	s := &Server{cfg: cfg, logger: log.New(&logs, "", 0)}
+	s.OpenFamilyStore()
+	b, _ := os.ReadFile(path)
+	if strings.Contains(string(b), household) {
+		t.Fatalf("family.json still holds the session value after the start: %s", b)
+	}
+	if !strings.Contains(logs.String(), "1 session(s) stored the old way were rewritten as fingerprints") {
+		t.Errorf("the conversion must be logged by count, got %q", logs.String())
+	}
+	if strings.Contains(logs.String(), household) {
+		t.Error("the log line carries the session value")
+	}
+}