Split i18n catalogues into per-domain modules

sv.ts/en.ts were single 602-line files that every feature had to edit,
making concurrent work on unrelated screens collide constantly. Split
both into per-domain modules (common, auth, calendar, dashboard,
settings, plan, wishEditor, tips) composed by an index that preserves
the existing `import { sv } from './sv'` specifier, so no consumer
changes.

Typing still catches drift in both directions: each en module is checked
against TranslationKey, and the composed catalogue must satisfy
Record<TranslationKey, string>.

All 433 keys and their values are byte-identical to the originals,
verified by diffing the parsed catalogues against the pre-split files.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RXMhc9nT6sNz1SL4j8dznL

frontend/src/i18n/sv/index.ts

@@ -0,0 +1,32 @@
+import { common } from './common'
+import { auth } from './auth'
+import { calendar } from './calendar'
+import { dashboard } from './dashboard'
+import { settings } from './settings'
+import { plan } from './plan'
+import { wishEditor } from './wishEditor'
+import { tips } from './tips'
+
+/**
+ * Swedish message catalogue — the single source of truth for translation keys.
+ *
+ * Split into per-domain modules so unrelated features can add keys without
+ * editing the same file. `en/` mirrors this structure exactly and is typed
+ * against `TranslationKey`, so a key present in one locale and missing from
+ * the other is a compile-time (`npm run typecheck`) error.
+ *
+ * These strings were extracted verbatim from the components that previously
+ * hardcoded them — this file is the authoritative Swedish copy.
+ */
+export const sv = {
+  ...common,
+  ...auth,
+  ...calendar,
+  ...dashboard,
+  ...settings,
+  ...plan,
+  ...wishEditor,
+  ...tips,
+} as const
+
+export type TranslationKey = keyof typeof sv