agent: lumotia-rebrand — frontend strings (svelte + i18n + design-system)

Phase 8 of the rebrand cascade. Every rendered string is now Lumotia;
no Magnotia surface visible in the UI.

Sweep replaced \bmagnotia\b -> lumotia and \bMagnotia\b -> Lumotia
across all .svelte / .ts / .js / .css / .html / .json (excluding
package-lock.json which regenerates, target/, build/, node_modules/).

Surfaces touched:
- src/app.css — design-token comment header and .magnotia-rh-* CSS
  resize-handle class selectors (also the consuming elements in
  components/ResizeHandles.svelte and src/routes/*/+layout.svelte).
- src/lib/i18n/locales/{en,de,es}.json — brand name in translations.
- src/lib/i18n/index.ts — header comment.
- src/lib/Sidebar.svelte and most pages under src/lib/pages/ +
  src/lib/components/ — title bars, document titles, default
  filenames (lumotia-YYYY-MM-DD.* etc), toast strings, error
  messages, dialog headers.
- src/routes/+layout.svelte, +page.svelte, viewer/, float/, preview/.
- src/app.html page <title>.
- src/lib/utils/settingsMigrations.ts — fallback toast copy.
- src/design-system/{colors_and_type.css,SKILL.md,README.md,
  ui_kits/{Sidebar.jsx,index.html}} — design-tokens, doc strings,
  preview wordmark in the kit.
- package.json — name + description.

NOT touched (deferred / immutable):
- package-lock.json — regenerates on next npm install.
- The two migration-call sites in stores reference the legacy magnotia
  keys deliberately; restored after the sweep clobbered them.
- docs/, README.md, HANDOVER.md — Phase 9 scope.

npm run check: 0 errors / 0 warnings (3958 files).
cargo test --workspace: 339 pass / 0 fail.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -1,7 +1,7 @@
 {
-  "name": "magnotia",
+  "name": "lumotia",
   "version": "0.1.0",
-  "description": "Magnotia — Think out loud",
+  "description": "Lumotia — Think out loud",
   "type": "module",
   "scripts": {
     "dev": "npm run dev:frontend",