fix(web): prefill birthday in contact form for imported contacts

internal/web/server_test.go

@@ -1,6 +1,7 @@
 package web
 
 import (
+	"fmt"
 	"io"
 	"log/slog"
 	"net/http"
@@ -10,6 +11,7 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
 
 	"git.arnef.de/arnef/nidus/internal/config"
 	"git.arnef.de/arnef/nidus/internal/db"
@@ -316,3 +318,24 @@ func TestAccountChangePassword(t *testing.T) {
 		t.Fatal("expected password to have changed")
 	}
 }
+
+func TestBirthdayInputValueNormalizesFormats(t *testing.T) {
+	year := time.Now().Year()
+	cases := []struct {
+		in   string
+		want string
+	}{
+		{"", ""},
+		{"19920217", "1992-02-17"},                  // vCard 3.0 compact
+		{"19540805", "1954-08-05"},                  // compact, no VALUE param
+		{"--0219", fmt.Sprintf("%04d-02-19", year)}, // year-less -> current year
+		{"2026-09-06", "2026-09-06"},                // already dashed (web-created)
+		{"1604-02-27", "1604-02-27"},                // dashed, ancient year preserved
+		{"garbage", "garbage"},                      // unrecognized passes through
+	}
+	for _, c := range cases {
+		if got := birthdayInputValue(c.in); got != c.want {
+			t.Errorf("birthdayInputValue(%q) = %q, want %q", c.in, got, c.want)
+		}
+	}
+}