panel: place drill-down back links under the heading

The user form had Back to users at the bottom of the card; all drill-down
pages now use a shared back_link template with a structural test.

Co-Authored-By: Claude <Composer 2.5> <noreply@anthropic.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

CHANGELOG.md

@@ -5,6 +5,13 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
 
 ## [Unreleased]
 
+### Fixed
+
+- panel: the user create/edit form placed «Back to users» at the bottom of the
+  card instead of under the heading like the delivery, domain, and domain-delete
+  pages. A shared `back_link` template now renders every drill-down up-link, and
+  `TestDrillDownPagesPlaceBackLinkAboveContent` guards its position.
+
 ### Changed
 
 - panel: **Settings** shows panel credentials and DMARC aggregate reports side

internal/web/view/templates/delivery.html

@@ -18,7 +18,7 @@
   <span class="st st-{{.Level}}">{{.Row.Status}}</span>
 </p>
 
-<a class="back" href="{{.BackURL}}">&larr; Back to deliveries</a>
+{{template "back_link" (back .BackURL "Back to deliveries")}}
 
 {{/* The two columns: what was recorded on the left, in what order it happened
      on the right. They are a pair — the facts are only worth reading against

internal/web/view/templates/domain_delete.html

@@ -1,7 +1,7 @@
 {{define "content"}}
 <h1>Delete {{.Domain.Name}}</h1>
 
-<a class="back" href="/domains/{{.Domain.ID}}">&larr; Back to {{.Domain.Name}}</a>
+{{template "back_link" (back (printf "/domains/%d" .Domain.ID) (printf "Back to %s" .Domain.Name))}}
 
 <div class="card">
   <h2>Confirm deletion</h2>

internal/web/view/templates/domain_detail.html

@@ -1,7 +1,7 @@
 {{define "content"}}
 <h1>{{.Domain.Name}}</h1>
 
-<a class="back" href="/domains">&larr; All domains</a>
+{{template "back_link" (back "/domains" "All domains")}}
 
 {{if .Flash}}<div class="flash">{{.Flash}}</div>{{end}}
 {{if .RateLimitErr}}<div class="flash error">{{.RateLimitErr}}</div>{{end}}

internal/web/view/templates/layout.html

@@ -107,6 +107,14 @@
      so its definition replaces the empty one. */}}
 {{define "wide"}}{{end}}
 
+{{/* back_link — up-navigation on drill-down pages. Invoke with the "back"
+     function, e.g. {{template "back_link" (back "/users" "Back to users")}}.
+     Place it directly under the page <h1> and above the cards (see .back in
+     panel.css). TestDrillDownPagesPlaceBackLinkAboveContent guards this. */}}
+{{define "back_link"}}
+<a class="back" href="{{.Href}}">&larr; {{.Label}}</a>
+{{end}}
+
 {{/* Navigation icons. Inline SVG rather than an icon font or sprite file: they
      inherit the link's colour through currentColor, cost no extra request, and
      need no exemption from the panel's "default-src 'self'" policy. Each is

internal/web/view/templates/user_form.html

@@ -1,6 +1,8 @@
 {{define "content"}}
 <h1>{{if .IsEdit}}Edit user{{else}}Create user{{end}}</h1>
 
+{{template "back_link" (back "/users" "Back to users")}}
+
 <div class="card narrow">
   {{if .Error}}<p class="error">{{.Error}}</p>{{end}}
   <form method="post" action="{{if .IsEdit}}/users/{{.UserID}}{{else}}/users/new{{end}}">
@@ -33,6 +35,5 @@
     <button type="submit" name="action" value="delete" class="danger">Delete user</button>
     {{end}}
   </form>
-  <p class="muted"><a href="/users">Back to users</a></p>
 </div>
 {{end}}

internal/web/view/templates_test.go

@@ -279,6 +279,32 @@ func TestOnlyThePagesMadeOfDataDeclareThemselvesWide(t *testing.T) {
 	}
 }
 
+// Drill-down pages carry an up-link directly under the heading and above the
+// cards. A link at the bottom of a form is easy to miss and drifts from the
+// rest of the panel, so the shared back_link template is mandatory on those
+// pages and TestDrillDownPagesPlaceBackLinkAboveContent guards its position.
+func TestDrillDownPagesPlaceBackLinkAboveContent(t *testing.T) {
+	drillDown := map[string]bool{
+		"user_form.html":     true,
+		"domain_detail.html": true,
+		"domain_delete.html": true,
+		"delivery.html":      true,
+	}
+	forEachTemplate(t, func(name, body string) {
+		if !drillDown[name] {
+			return
+		}
+		if !strings.Contains(body, `template "back_link"`) {
+			t.Errorf("%s is a drill-down page but does not use the shared back_link template", name)
+		}
+		backIdx := strings.Index(body, `template "back_link"`)
+		cardIdx := strings.Index(body, `class="card`)
+		if cardIdx >= 0 && backIdx > cardIdx {
+			t.Errorf("%s places the back link after the first card", name)
+		}
+	})
+}
+
 // Since the panel root redirects to the status page, a link left pointing at
 // "/" silently lands on the wrong screen instead of failing — so no template may
 // contain one.

internal/web/view/view.go

@@ -65,7 +65,7 @@ func New(version string) (*Engine, error) {
 	}
 	for name, files := range pageFiles {
 		patterns := append([]string{"templates/layout.html"}, files...)
-		tmpl, err := template.New("layout.html").ParseFS(assetsFS, patterns...)
+		tmpl, err := template.New("layout.html").Funcs(templateFuncs()).ParseFS(assetsFS, patterns...)
 		if err != nil {
 			return nil, fmt.Errorf("parse template %s: %w", name, err)
 		}
@@ -81,6 +81,17 @@ func New(version string) (*Engine, error) {
 	return e, nil
 }
 
+// templateFuncs supplies helpers shared across page templates.
+func templateFuncs() template.FuncMap {
+	return template.FuncMap{
+		// back builds the map back_link reads; keeps href and label paired at
+		// the call site instead of repeating the <a class="back"> markup.
+		"back": func(href, label string) map[string]string {
+			return map[string]string{"Href": href, "Label": label}
+		},
+	}
+}
+
 // Page returns a parsed page template by logical name. It is exported for
 // template guard tests that assert structural properties across all pages.
 func (e *Engine) Page(name string) *template.Template {