Rename AdventureLog to Voyage and add fork attribution

- Replace all AdventureLog references with Voyage across ~102 files
  (7 case variants: AdventureLog, adventurelog, Adventurelog, ADVENTURELOG,
  AdventUrelog, AdventureLOG, adventure-log, adventure_log)
- Rename brand, static, and documentation assets to use voyage naming
- Rename install_adventurelog.sh → install_voyage.sh
- Update README.md and voyage_overview.md to credit AdventureLog as
  the upstream project and Sean Morley as its original creator

frontend/src/routes/worldtravel/+page.svelte

@@ -728,7 +728,7 @@
 								</div>
 								<a
 									class="link link-primary mt-4 inline-block"
-									href="https://adventurelog.app/docs/configuration/updating.html#updating-the-region-data"
+									href="https://voyage.app/docs/configuration/updating.html#updating-the-region-data"
 									target="_blank"
 								>
 									{$t('settings.documentation_link')}