feat(go): M6.2 — adults page (table, filters, credits/debts/unmatched, Pay buttons)

- Extract AssembleAdults(ctx) from ServeAdults so HTML and JSON API share one reconcile path.
- HTMLHandler gains *api.Handler; ServeAdults loads real data and renders adults.tmpl.
- AdultsPageData view model + qrHref/qrHrefAll funcMap (URL-encode /qr params, YYYY-MM→MM/YYYY).
- adults.tmpl: full reconcile table, per-cell status classes + cell-unpaid-current, Pay button hrefs,
  totals row, credits/debts/unmatched sections, filter controls, sheet links.
- static/js/filters.js: NFD-normalize name filter + month-range column hiding; future months hidden by default.
- TestAdultsPage asserts member name and cell text against fixture data.

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

go/internal/web/html_handler_test.go

@@ -1,21 +1,61 @@
 package web_test
 
 import (
+	"context"
 	"fmt"
+	"fuj-management/go/internal/config"
+	"fuj-management/go/internal/domain/reconcile"
 	"fuj-management/go/internal/web"
+	"fuj-management/go/internal/web/api"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
 )
 
+// fixtureSources returns one adult ("Test Member", tier A) with a 2026-01 fee
+// of 750 CZK (4 sessions) and a matching payment of 750 — mirrors Python's
+// test_adults_route fixture.
+type fixtureSources struct{}
+
+func (fixtureSources) LoadAdults(_ context.Context) ([]reconcile.Member, []string, error) {
+	return []reconcile.Member{
+		{Name: "Test Member", Tier: "A", Fees: map[string]reconcile.FeeData{
+			"2026-01": {Expected: 750, Attendance: 4},
+		}},
+	}, []string{"2026-01"}, nil
+}
+
+func (fixtureSources) LoadJuniors(_ context.Context) ([]reconcile.Member, []string, error) {
+	return nil, nil, nil
+}
+
+func (fixtureSources) LoadTransactions(_ context.Context) ([]reconcile.Transaction, error) {
+	amt := float64(750)
+	return []reconcile.Transaction{
+		{Date: "2026-01-01", Amount: 750, Person: "Test Member", Purpose: "2026-01", InferredAmount: &amt},
+	}, nil
+}
+
+func (fixtureSources) LoadExceptions(_ context.Context) (map[reconcile.ExceptionKey]reconcile.Exception, error) {
+	return nil, nil
+}
+
+func fixtureHandler(t *testing.T) *api.Handler {
+	t.Helper()
+	return &api.Handler{
+		Sources: fixtureSources{},
+		Config:  config.Config{BankAccount: "CZ0000000000000000000000"},
+	}
+}
+
 func TestHTMLHandlerSmoke(t *testing.T) {
 	renderer, err := web.NewRenderer()
 	if err != nil {
 		t.Fatalf("NewRenderer: %v", err)
 	}
 	b := web.BuildInfo{Version: "v0", Commit: "abc1234", BuildDate: "2026-01-01"}
-	h := web.NewHTMLHandler(renderer, b)
+	h := web.NewHTMLHandler(renderer, b, fixtureHandler(t))
 
 	cases := []struct {
 		path    string
@@ -52,3 +92,37 @@ func TestHTMLHandlerSmoke(t *testing.T) {
 		})
 	}
 }
+
+func TestAdultsPage(t *testing.T) {
+	renderer, err := web.NewRenderer()
+	if err != nil {
+		t.Fatalf("NewRenderer: %v", err)
+	}
+	b := web.BuildInfo{Version: "v0", Commit: "abc1234", BuildDate: "2026-01-01"}
+	h := web.NewHTMLHandler(renderer, b, fixtureHandler(t))
+
+	req := httptest.NewRequest(http.MethodGet, "/adults", nil)
+	w := httptest.NewRecorder()
+	h.ServeAdults(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status = %d, want 200", w.Code)
+	}
+
+	body := w.Body.String()
+
+	for _, want := range []string{
+		"Adults Dashboard",
+		"Test Member",
+		"750/750 CZK (4)", // paid/expected (attendance)
+	} {
+		if !strings.Contains(body, want) {
+			t.Errorf("body missing %q", want)
+		}
+	}
+
+	// Python assertion: cell text never says literally "OK"
+	if strings.Contains(body, ">OK<") {
+		t.Error("body should not contain >OK<")
+	}
+}