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, 5 insertions, 1 deletions

diff --git a/src/lib/Utility/Loading.svelte b/src/lib/Utility/Loading.svelte
index 67691cbb..a84570b7 100644
--- a/src/lib/Utility/Loading.svelte
+++ b/src/lib/Utility/Loading.svelte
@@ -1,4 +1,6 @@
 <script lang="ts">
+import locale from "$stores/locale";
+
 export let type: string | undefined = undefined;
 export let percent: number | undefined = undefined;
 export let card = true;
@@ -6,7 +8,9 @@ export let card = true;
 
 <div class:card>
   {#if type}
-    Loading {type} ...{percent ? ` ${percent}%` : ''}
+    {$locale({
+      values: { type, percent: percent ? ` ${percent}%` : '' }
+    }).common?.loading ?? `Loading ${type} ...${percent ? ` ${percent}%` : ''}`}
   {:else}
     <slot />
   {/if}