fix: correct final whole-branch review findings for 0.6.6 English content

- TRAVELLING spelling: fix TRAVELING -> TRAVELLING in travel-panel.component.html
  to match UK spelling used everywhere else (world/hunting/combat stores + API
  error messages)
- Grenzwacht -> Border Watch: fix stale German faction display name in
  reputation-display, reputation.service/controller, turn-in.service specs,
  and the vertical-slice seed spec test title
- Suedtor von Graufurt -> Graufurt South Gate: fix stale ASCII-transliterated
  German location name in hunting.service.spec.ts
- Aschenfelder(n) -> Ashen Fields: fix stale German location name/description
  in top-bar.component.spec.ts and context-panel.component.spec.ts (key
  identifiers left untouched)
- Fix 7 test titles still describing translated error messages as "German"
  across world/hunting/inventory/combat store specs
- README: update demo location names from German to their current English
  names (Graufurt South Gate, Burned Road)
- item-rarity.enum.ts: fix now-false comment claiming rarity labels are
  German; the frontend RARITY_LABELS map is English

Pure literal-string/comment substitutions; no keys, ids, or logic changed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ACkMEDYiwtcfchqKkiUJNX

apps/api/src/database/seeds/vertical-slice.seed.spec.ts

@@ -606,7 +606,7 @@ describe('seedVisibleVerticalSlice', () => {
     );
   });
 
-  it('seeds the Grenzwacht faction', async () => {
+  it('seeds the Border Watch faction', async () => {
     const reputationFactionRepository = new InMemoryRepository();
     const dataSource = createDataSource(
       new InMemoryRepository(),