release: 1.1.0: Domain-admin role and internal/web package split

The first MINOR after 1.0.0: send-only DMARC guidance in the panel, AGPL packaging on every page, and an internal split of `internal/web` ahead of domain-admin work. Upgrading runs one SQLite migration (empty defaults; existing DNS guidance is unchanged until you set a report address).
Changed:
  - `internal/web` split into subpackages (`web/view`, `web/auth`, `web/validate`,
Added:
  - panel: DMARC guidance for send-only relays — the suggested `_dmarc` record
  - AGPL packaging hygiene: [NOTICE](NOTICE) names the copyright holder and the
  - [docs/roadmap.md](docs/roadmap.md) — candidate item **visual-style** (panel

Full detail: CHANGELOG.md (1.1.0).

internal/web/view/templates/domain_delete.html

@@ -0,0 +1,24 @@
+{{define "content"}}
+<h1>Delete {{.Domain.Name}}</h1>
+
+<a class="back" href="/domains/{{.Domain.ID}}">&larr; Back to {{.Domain.Name}}</a>
+
+<div class="card">
+  <h2>Confirm deletion</h2>
+  <p>You are about to delete <strong>{{.Domain.Name}}</strong>. This will:</p>
+  <ul>
+    <li>permanently delete its DKIM signing key;</li>
+    <li>delete
+      {{if eq .Domain.AppCount 0}}its (currently none) bound applications{{else}}
+      <strong>all {{.Domain.AppCount}} bound application(s)</strong>, including
+      their SASL credentials and sender bindings{{end}};</li>
+    <li>reload OpenDKIM so the domain is no longer signed.</li>
+  </ul>
+  <p class="muted">This cannot be undone. The published DKIM DNS record becomes
+  invalid; remove it from DNS if you do not plan to re-add the domain.</p>
+
+  <form method="post" action="/domains/{{.Domain.ID}}/delete">
+    <button type="submit" class="danger">Delete {{.Domain.Name}}</button>
+  </form>
+</div>
+{{end}}