ci: decouple deploy from mobile app, web-only pipeline

Mobile app is distributed via Play Store DApps browser, no longer
built/deployed from this repo. Deploy and security audit now only
depend on the web job passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/quality-gate.yml

@@ -117,7 +117,7 @@ jobs:
   deploy:
     name: Deploy Web
     runs-on: ubuntu-latest
-    needs: [web, mobile, security-audit]
+    needs: [web, security-audit]
     if: github.ref == 'refs/heads/main' && github.event_name == 'push'
 
     steps:
@@ -174,7 +174,7 @@ jobs:
   security-audit:
     name: Security Audit
     runs-on: ubuntu-latest
-    needs: [web, mobile]
+    needs: [web]
 
     steps:
       - name: Checkout code
@@ -191,12 +191,6 @@ jobs:
           npm install
           npm audit --audit-level=critical
 
-      - name: Mobile - npm audit (critical only)
-        working-directory: ./mobile
-        run: |
-          npm install --legacy-peer-deps
-          npm audit --audit-level=critical --production
-
       - name: TruffleHog Secret Scan
         uses: trufflesecurity/trufflehog@main
         with: