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

.github/workflows/trivy_security_scans.yml

@@ -57,15 +57,15 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build backend Docker image
-        run: docker build -t adventurelog-backend ./backend
+        run: docker build -t voyage-backend ./backend
 
       - name: Build frontend Docker image
-        run: docker build -t adventurelog-frontend ./frontend
+        run: docker build -t voyage-frontend ./frontend
 
       - name: Scan backend Docker image with Trivy
         uses: aquasecurity/trivy-action@master
         with:
-          image-ref: adventurelog-backend
+          image-ref: voyage-backend
           format: table
           exit-code: 1
           ignore-unfixed: true
@@ -75,7 +75,7 @@ jobs:
       - name: Scan frontend Docker image with Trivy
         uses: aquasecurity/trivy-action@master
         with:
-          image-ref: adventurelog-frontend
+          image-ref: voyage-frontend
           format: table
           exit-code: 1
           ignore-unfixed: true