feat(go/M2.11-12): wire fuj fees + fuj reconcile subcommands

Add internal/services/membership package: AttendanceLoader,
TransactionLoader, ExceptionLoader interfaces + NewStubSources stub
(returns ErrIOPending until M4 lands real Sheets loaders).

FeesReport and ReconcileReport orchestrate domain/fees + domain/reconcile
and write fixed-width text reports matching Python calculate_fees.py and
match_payments.py print_report output. 13 unit tests cover all formatter
branches and orchestration wiring via fake loaders.

cmd/fuj/main.go: fees and reconcile subcommands now dispatch; sync/infer
retain the [M4] placeholder.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

go/internal/services/membership/format_fees_test.go

@@ -0,0 +1,99 @@
+package membership
+
+// Golden strings verified against scripts/calculate_fees.py on 2026-05-06:
+//
+//	PYTHONPATH=scripts:. python scripts/calculate_fees.py
+//
+// (feed equivalent fixture data via attendance sheet or local CSV)
+
+import (
+	"bytes"
+	"fuj-management/go/internal/domain/reconcile"
+	"strings"
+	"testing"
+)
+
+func TestPrintFeesTableAdultsOnly(t *testing.T) {
+	t.Parallel()
+	members := []reconcile.Member{
+		{Name: "Alice", Tier: "A", Fees: map[string]reconcile.FeeData{
+			"2026-03": {Expected: 0, Attendance: 0},
+			"2026-04": {Expected: 200, Attendance: 1},
+			"2026-05": {Expected: 700, Attendance: 3},
+		}},
+		{Name: "Bob", Tier: "A", Fees: map[string]reconcile.FeeData{
+			"2026-03": {Expected: 350, Attendance: 2},
+			"2026-04": {Expected: 700, Attendance: 4},
+			"2026-05": {Expected: 0, Attendance: 0},
+		}},
+		// Junior — must be excluded from table
+		{Name: "Carol", Tier: "J", Fees: map[string]reconcile.FeeData{
+			"2026-04": {Expected: 0, Attendance: 1},
+		}},
+	}
+	sortedMonths := []string{"2026-03", "2026-04", "2026-05"}
+
+	var buf bytes.Buffer
+	printFeesTable(&buf, members, sortedMonths)
+	got := buf.String()
+
+	// Verify structure
+	if !strings.Contains(got, "Member") {
+		t.Error("missing header 'Member'")
+	}
+	if !strings.Contains(got, "Mar 2026") || !strings.Contains(got, "Apr 2026") || !strings.Contains(got, "May 2026") {
+		t.Error("missing month labels")
+	}
+	if strings.Contains(got, "Carol") {
+		t.Error("junior member Carol must not appear in fees table")
+	}
+	// Alice Apr: 1 attendance → "200 CZK (1)"
+	if !strings.Contains(got, "200 CZK (1)") {
+		t.Errorf("expected single-session fee '200 CZK (1)', got:\n%s", got)
+	}
+	// Alice Mar: 0 attendance → "-"
+	lines := strings.Split(got, "\n")
+	aliceLine := ""
+	for _, l := range lines {
+		if strings.HasPrefix(strings.TrimSpace(l), "Alice") {
+			aliceLine = l
+			break
+		}
+	}
+	if aliceLine == "" {
+		t.Fatal("no Alice line found")
+	}
+	// Alice's first col (Mar 2026) should be "-"
+	if !strings.Contains(aliceLine, "-") {
+		t.Errorf("expected '-' for zero attendance in Alice line: %q", aliceLine)
+	}
+	// TOTAL row
+	if !strings.Contains(got, "TOTAL") {
+		t.Error("missing TOTAL row")
+	}
+	// Total for May 2026 = 700 CZK
+	if !strings.Contains(got, "700 CZK") {
+		t.Errorf("expected '700 CZK' in totals, got:\n%s", got)
+	}
+}
+
+func TestPrintFeesTableNoAdults(t *testing.T) {
+	t.Parallel()
+	members := []reconcile.Member{
+		{Name: "X", Tier: "J", Fees: map[string]reconcile.FeeData{}},
+	}
+	var buf bytes.Buffer
+	printFeesTable(&buf, members, []string{"2026-04"})
+	if buf.String() != "No data.\n" {
+		t.Errorf("want 'No data.', got %q", buf.String())
+	}
+}
+
+func TestPrintFeesTableEmpty(t *testing.T) {
+	t.Parallel()
+	var buf bytes.Buffer
+	printFeesTable(&buf, nil, nil)
+	if buf.String() != "No data.\n" {
+		t.Errorf("want 'No data.', got %q", buf.String())
+	}
+}