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/setup.html

@@ -0,0 +1,21 @@
+{{define "content"}}
+<img class="mark" src="/static/logo.svg" width="330" height="150" alt="SelfPost">
+<h1>Create administrator</h1>
+<div class="card narrow">
+  <p class="muted">This one-time link creates the single panel administrator.
+  After you submit, the link stops working for good.</p>
+  {{if .Error}}<p class="error">{{.Error}}</p>{{end}}
+  <form method="post" action="/setup/{{.Token}}">
+    <label for="username">Username</label>
+    <input id="username" name="username" autocomplete="username" autofocus required>
+
+    <label for="password">Password</label>
+    <input id="password" name="password" type="password" autocomplete="new-password" required>
+
+    <label for="password_confirm">Confirm password</label>
+    <input id="password_confirm" name="password_confirm" type="password" autocomplete="new-password" required>
+
+    <button type="submit">Create administrator</button>
+  </form>
+</div>
+{{end}}