Fix CI: Auto-detect web/ changes for website build & deploy [web]

- Build website when files in web/ directory are modified
- Deploy website on workflow_dispatch without requiring [web] tag
- Keep backward compatibility with [web] commit message trigger

.github/workflows/unified-pipeline.yml

@@ -123,7 +123,10 @@ jobs:
   web-build:
     name: 🌐 Build Website
     runs-on: ubuntu-latest
-    if: contains(github.event.head_commit.message, '[web]') || github.event_name == 'workflow_dispatch'
+    if: |
+      contains(github.event.head_commit.message, '[web]') ||
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'push' && contains(join(github.event.commits.*.modified, ','), 'web/'))
     steps:
       - uses: actions/checkout@v4
 
@@ -154,7 +157,11 @@ jobs:
     name: 🚀 Deploy Website
     runs-on: ubuntu-latest
     needs: [python-test, web-build]
-    if: github.event_name == 'push' && github.ref == 'refs/heads/main' && contains(github.event.head_commit.message, '[web]')
+    if: |
+      github.ref == 'refs/heads/main' &&
+      (contains(github.event.head_commit.message, '[web]') ||
+       github.event_name == 'workflow_dispatch' ||
+       (github.event_name == 'push' && contains(join(github.event.commits.*.modified, ','), 'web/')))
     steps:
       - uses: actions/checkout@v4