release: 1.9.2: Review pass: port-25 milters, DMARC validation, rate-limit fix

Review pass over `1.4.0`…`1.9.1`: port 25 no longer shares the submission milter chain, DMARC reports are validated before they are stored, and the auto rate limit is correct for a non-default level-1 window. Schema migration `0010` (index only). Upgrading is a tag bump.
Added:
  - SQLite migration `0010_send_log_app_login_index.sql` —
  - DMARC aggregate reports are accepted as **zip** as well as gzip or plain XML
  - e2e: `checkPort25ConfigCombinations` regenerates the Postfix configuration
Changed:
  - README hero line and a **Positioning** block in `docs/product.md` record the
Fixed:
  - The setup account's password is hashed at bcrypt cost `12` like every other
  - Login/setup rate limiter: protecting blocked buckets from eviction is now
  - `postqueue -p` output is bounded to 4 MiB (the timeout alone left the size of
  - [schema-migrations.md](docs/schema-migrations.md): the schema section was
  - postqueue reader is now time-bounded: `postqueue -p` runs under a 5-second
  … (11 more in CHANGELOG)
Changed:
  - [roadmap.md](docs/roadmap.md) now carries everything the 2026-08-19 code
  - Extracted `internal/configsafe` — the empty-value and forbidden-character
  - Build, deploy and migration comments no longer cite the archived
  - Dropped the `parseDomainRateLimitForm` / `parseAppRateLimitForm` pass-through
  - Extracted shared helpers: `internal/atomicfile` (atomic temp-write+rename) and
  … (7 more in CHANGELOG)
Removed:
  - Unused legacy asset `docs/assets/icon.png` (superseded by the four brand SVGs
  - Plan documents for already-shipped features: `domain-stats-auto-ratelimit`,

Full detail: CHANGELOG.md (1.9.2).

docs/assets/panel-redesign/panel/src/backup.html

@@ -0,0 +1,44 @@
+<!-- title: Backup | section: server | page: backup -->
+    <div class="sp-head">
+      <div class="sp-grow">
+        <p class="sp-kicker">Server</p>
+        <h1 class="title is-3">Backup</h1>
+        <p class="sp-lead">Take the whole instance with you, or bring one domain in from another SelfPost. Both files are secrets.</p>
+      </div>
+    </div>
+
+    <div class="columns">
+      <div class="column is-6">
+        <div class="box">
+          <div class="sp-box-head"><span class="sp-no">01</span><h2>Full backup</h2></div>
+          <div class="sp-box-body">
+            <p class="mb-3"><code>data/</code> (database, DKIM keys, credentials, the queue), <code>docker-compose.yml</code>, <code>.env</code> and <code>certs/</code> in one archive. Restore into an empty project directory and start the <strong>same SelfPost version</strong>. The reverse-proxy vhost is not included.</p>
+            <form class="sp-form" method="post" action="#">
+              <div class="field"><label class="checkbox"><input type="checkbox" name="encrypt" checked> Encrypt with a password (<code>.spbk</code>)</label></div>
+              <div class="sp-pair">
+                <div class="field"><label class="label" for="pw">Password</label><div class="control"><input class="input" id="pw" type="password" placeholder="at least 12 characters"></div></div>
+                <div class="field"><label class="label" for="pw2">Repeat password</label><div class="control"><input class="input" id="pw2" type="password"></div></div>
+              </div>
+              <p class="help mb-3">Keep this password: SelfPost does not store it, and the file cannot be opened without it.</p>
+              <button type="submit" class="button is-primary"><i class="ti ti-download"></i>Download full backup</button>
+            </form>
+          </div>
+        </div>
+      </div>
+
+      <div class="column is-6">
+        <div class="box" id="import">
+          <div class="sp-box-head"><span class="sp-no">02</span><h2>Import a domain</h2></div>
+          <div class="sp-box-body">
+            <p class="mb-3">A domain export from another instance — plain <code>.json</code> or encrypted <code>.spde</code>. Its DKIM key and application passwords come across, so the published DNS needs no change. The export itself is made on the <a href="out-domain-settings.html#export">domain's settings</a>.</p>
+            <form class="sp-form" method="post" action="out-domain.html" enctype="multipart/form-data">
+              <div class="field"><label class="label">Domain export file</label>
+                <div class="file has-name is-fullwidth"><label class="file-label"><input class="file-input" type="file" name="file" accept=".json,.spde"><span class="file-cta"><i class="ti ti-upload"></i><span class="file-label ml-2">Choose a file…</span></span><span class="file-name">example.org.spde</span></label></div></div>
+              <div class="field"><label class="label" for="ipw">Password</label><div class="control"><input class="input" id="ipw" name="import_password" type="password" autocomplete="off"></div>
+                <p class="help">Asked only for an encrypted <code>.spde</code> file.</p></div>
+              <button type="submit" class="button is-primary"><i class="ti ti-file-import"></i>Import domain</button>
+            </form>
+          </div>
+        </div>
+      </div>
+    </div>