chore(release): bump version to 1.2.13 "400+ stars"

Version bumped across Cargo.toml, tauri.conf.json, package.json, snapcraft.yaml (version + source-tag), flake.nix, and the lockfiles. metainfo.xml gains a 1.2.13 release entry, the About modal codename becomes "400+ stars", and the README contributors list adds @Vudgekek and @DoubleGate.

cc

src/lib/components/AboutModal.svelte

@@ -99,7 +99,7 @@
             <span class="label">{$t('about.buildInfo.version')}</span>
             <span class="value">{appVersion}</span>
             <span class="label">{$t('about.buildInfo.codename')}</span>
-            <span class="value codename">Exclusive Hardening</span>
+            <span class="value codename">400+ stars</span>
             <span class="label">{$t('about.buildInfo.license')}</span>
             <span class="value">MIT</span>
             <span class="label">{$t('about.buildInfo.platform')}</span>