refactor(locale): move hardcoded UI strings into english locale

Adds optional namespaces (common, errors, commandPalette, headTitle,
notifications, schedule, events, home, reader, routes, badgePreview,
badgeWall) and extends existing ones (settings.*, lists.*, tools.*,
user.*, hololive.*) on the Locale interface. New fields are optional
so japanese.ts can omit them; svelte-i18n's fallbackLocale handles
the runtime miss.

HeadTitle gains an optional routeKey prop for type-safe lookup.
defaultActions becomes a factory so the command palette re-reads
locale on language toggle. The existing JP feedback translation
in routes/settings is preserved via japanese.ts.

Out of scope (kept hardcoded): service-worker.ts, app.html,
Landing*.svelte, tools.ts registry, Easter Event 2025 pages.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/lib/User/BadgeWall/FallbackBadge.svelte b/src/lib/User/BadgeWall/FallbackBadge.svelte
index a930e5e0..04793aa0 100644
--- a/src/lib/User/BadgeWall/FallbackBadge.svelte
+++ b/src/lib/User/BadgeWall/FallbackBadge.svelte
@@ -113,7 +113,12 @@ const asAWCBadge = (b: Badge | AWCBadge) => b as AWCBadge;
     </a>
   </Tooltip>
 {:else if !hideOnError}
-  <img src={error} alt="Not found" loading="lazy" class="badge" />
+  <img
+    src={error}
+    alt={$locale().badgeWall?.notFound ?? 'Not found'}
+    loading="lazy"
+    class="badge"
+  />
 {/if}
 
 <style lang="scss">