feat(go): M6.3 — juniors page (table, filters, credits/debts, Pay buttons)

- Extract AssembleJuniors(ctx) from ServeJuniors JSON handler so HTML
  and JSON share the same view-model path (mirrors AssembleAdults pattern)
- Add JuniorsPageData wrapper in render.go
- Wire HTMLHandler.ServeJuniors to AssembleJuniors + render template
- Replace 4-line placeholder juniors.tmpl with full template:
  member table, name filter, month-range filter, totals row,
  Credits + Debts sections, Pay / Pay All buttons via /qr links
  (no Unmatched section — matches Python juniors.html parity)
- J/A attendance breakdown ("3/500 CZK (4:2J,1A)") and "?" sentinel
  rendered via MonthCell.Text from buildJuniorMemberRow, no extra
  template logic needed
- All tests pass; make parity reports 3/3 routes OK

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

go/internal/web/api/handler.go

@@ -55,14 +55,23 @@ func (h *Handler) AssembleAdults(ctx context.Context) (AdultsResponse, error) {
 
 // ServeJuniors handles GET /api/juniors.
 func (h *Handler) ServeJuniors(w http.ResponseWriter, r *http.Request) {
-	ctx := r.Context()
-	members, sortedMonths, txns, exceptions, err := h.loadAll(ctx, false)
+	resp, err := h.AssembleJuniors(r.Context())
 	if err != nil {
 		h.writeError(w, r, err)
 		return
 	}
+	writeJSON(w, resp)
+}
+
+// AssembleJuniors loads all data and builds the juniors view model.
+// Shared between the JSON API route and the HTML handler.
+func (h *Handler) AssembleJuniors(ctx context.Context) (JuniorsResponse, error) {
+	members, sortedMonths, txns, exceptions, err := h.loadAll(ctx, false)
+	if err != nil {
+		return JuniorsResponse{}, err
+	}
 	result := domreconcile.Reconcile(members, sortedMonths, txns, exceptions, time.Now().Year())
-	writeJSON(w, buildJuniorsResponse(members, sortedMonths, result, txns, h.Config, time.Now().Format("2006-01")))
+	return buildJuniorsResponse(members, sortedMonths, result, txns, h.Config, time.Now().Format("2006-01")), nil
 }
 
 // ServePayments handles GET /api/payments.

go/internal/web/html_handler.go

@@ -33,7 +33,18 @@ func (h *HTMLHandler) ServeAdults(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *HTMLHandler) ServeJuniors(w http.ResponseWriter, r *http.Request) {
-	h.renderer.Render(w, "juniors", PageData{Active: "juniors", Build: h.build})
+	data, err := h.apiHandler.AssembleJuniors(r.Context())
+	if err != nil {
+		h.renderer.Render(w, "juniors", JuniorsPageData{
+			PageData: PageData{Active: "juniors", Build: h.build},
+			Error:    err.Error(),
+		})
+		return
+	}
+	h.renderer.Render(w, "juniors", JuniorsPageData{
+		PageData: PageData{Active: "juniors", Build: h.build},
+		Data:     data,
+	})
 }
 
 func (h *HTMLHandler) ServePayments(w http.ResponseWriter, r *http.Request) {

go/internal/web/render.go

@@ -23,6 +23,13 @@ type AdultsPageData struct {
 	Error string
 }
 
+// JuniorsPageData is the view model for the /juniors HTML page.
+type JuniorsPageData struct {
+	PageData
+	Data  api.JuniorsResponse
+	Error string
+}
+
 // Renderer parses and executes HTML templates from the embedded FS.
 type Renderer struct {
 	tmpls map[string]*template.Template

go/internal/web/templates/juniors.tmpl

@@ -1,5 +1,121 @@
 {{define "title"}}Juniors{{end}}
 {{define "content"}}
 <h1>Juniors Dashboard</h1>
-<p class="description">Coming in M6.3</p>
+
+{{if .Error}}
+<div class="description">Error loading data: {{.Error}}</div>
+{{else}}
+
+<div class="description">
+  Balances calculated by matching Google Sheet payments against attendance fees.<br>
+  Source: <a href="{{.Data.AttendanceURL}}" target="_blank" rel="noopener">Attendance Sheet</a> |
+  <a href="{{.Data.PaymentsURL}}" target="_blank" rel="noopener">Payments Ledger</a>
+</div>
+
+<div class="filter-container" id="filterContainer" data-current-month="{{.Data.CurrentMonth}}">
+  <div class="filter-item">
+    <label class="filter-label" for="nameFilter">Member</label>
+    <input id="nameFilter" class="filter-input" type="text" placeholder="Filter by name…">
+  </div>
+  <div class="filter-item">
+    <label class="filter-label" for="fromMonth">From</label>
+    <select id="fromMonth" class="filter-select">
+      <option value="">All</option>
+      {{range $i, $m := .Data.Months}}
+      <option value="{{$i}}">{{$m}}</option>
+      {{end}}
+    </select>
+  </div>
+  <div class="filter-item">
+    <label class="filter-label" for="toMonth">To</label>
+    <select id="toMonth" class="filter-select">
+      <option value="">All</option>
+      {{range $i, $m := .Data.Months}}
+      <option value="{{$i}}">{{$m}}</option>
+      {{end}}
+    </select>
+  </div>
+  <div class="filter-item">
+    <button id="applyFilter" class="filter-select" type="button" style="cursor: pointer;">Apply</button>
+    <button id="clearFilter" class="filter-select" type="button" style="cursor: pointer;">All</button>
+  </div>
+</div>
+
+{{if .Data.Results}}
+<div class="table-container">
+<table>
+  <thead>
+    <tr>
+      <th>Member</th>
+      {{range $i, $m := .Data.Months}}
+      <th data-month-idx="{{$i}}" data-raw-month="{{index $.Data.RawMonths $i}}">{{$m}}</th>
+      {{end}}
+      <th>Balance</th>
+    </tr>
+  </thead>
+  <tbody>
+    {{range $row := .Data.Results}}
+    <tr class="member-row" data-name="{{$row.Name}}">
+      <td class="member-name">{{$row.Name}}</td>
+      {{range $i, $cell := $row.Months}}
+      <td data-month-idx="{{$i}}" title="{{$cell.Tooltip}}"
+          class="{{if eq $cell.Status "empty"}}cell-empty{{else if and (or (eq $cell.Status "unpaid") (eq $cell.Status "partial")) (ge $cell.RawMonth $.Data.CurrentMonth)}}cell-unpaid-current{{else if or (eq $cell.Status "unpaid") (eq $cell.Status "partial")}}cell-unpaid{{else if eq $cell.Status "ok"}}cell-ok{{end}}{{if $cell.Overridden}} cell-overridden{{end}}">
+        {{$cell.Text}}
+        {{if and (or (eq $cell.Status "unpaid") (eq $cell.Status "partial")) (lt $cell.RawMonth $.Data.CurrentMonth)}}
+        <a class="pay-btn" href="{{qrHref $.Data.BankAccount $cell.Amount $row.Name $cell.RawMonth}}">Pay</a>
+        {{end}}
+      </td>
+      {{end}}
+      <td class="{{if lt $row.Balance 0}}balance-neg{{else if gt $row.Balance 0}}balance-pos{{end}}" style="position: relative;">
+        {{$row.Balance}}
+        {{if gt $row.PayableAmount 0}}
+        <a class="pay-btn" href="{{qrHrefAll $.Data.BankAccount $row.PayableAmount $row.Name $row.RawUnpaidPeriods}}">Pay All</a>
+        {{end}}
+      </td>
+    </tr>
+    {{end}}
+    <tr class="totals-row" style="font-weight: bold; background-color: #111; border-top: 2px solid #333;">
+      <td style="text-align: left; padding: 6px 8px;">TOTAL</td>
+      {{range $i, $t := .Data.Totals}}
+      <td data-month-idx="{{$i}}" data-raw-month="{{index $.Data.RawMonths $i}}" class="{{if eq $t.Status "ok"}}cell-ok{{else if eq $t.Status "unpaid"}}cell-unpaid{{else if eq $t.Status "surplus"}}cell-overridden{{end}}" style="padding-top: 4px; padding-bottom: 4px;">
+        <span style="font-size: 0.6em; font-weight: normal; color: #666; text-transform: lowercase; display: block; margin-bottom: 2px;">received / expected</span>
+        {{$t.Text}}
+      </td>
+      {{end}}
+      <td></td>
+    </tr>
+  </tbody>
+</table>
+</div>
+{{else}}
+<div class="description">No members found.</div>
+{{end}}
+
+{{if .Data.Credits}}
+<h2>Credits (Advance Payments / Surplus)</h2>
+<div class="list-container">
+  {{range .Data.Credits}}
+  <div class="list-item">
+    <span class="list-item-name">{{.Name}}</span>
+    <span class="list-item-val">{{.Amount}} CZK</span>
+  </div>
+  {{end}}
+</div>
+{{end}}
+
+{{if .Data.Debts}}
+<h2>Debts (Missing Payments)</h2>
+<div class="list-container">
+  {{range .Data.Debts}}
+  <div class="list-item">
+    <span class="list-item-name">{{.Name}}</span>
+    <span class="list-item-val" style="color: #ff3333;">{{.Amount}} CZK</span>
+  </div>
+  {{end}}
+</div>
+{{end}}
+
+{{end}}
+
+<script src="/static/js/filters.js" defer></script>
 {{end}}