ci: also skip backend build+deploy on frontend-only commits

deploy.yml builds + ships the BACKEND /api image to the VPS only; the
frontend deploys independently via Vercel. A frontend-only commit was
still busting the Docker cache at `COPY . .` (frontend/ is in the build
context), pushing a fresh GHCR image, and force-recreating the prod
backend container — for a change the backend never serves.

Added 'frontend/**' to the existing paths-ignore. Frontend-only and
docs-only commits now skip this pipeline entirely (Vercel still
deploys the frontend); mixed commits touching backend/src still deploy.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: LEANDERANTONY

.github/workflows/deploy.yml

@@ -3,13 +3,17 @@ name: Build & Deploy
 on:
   push:
     branches: [main]
-    # Docs-only commits don't change the runtime image — skip the
-    # build + VPS container recreate. A mixed code+docs commit still
-    # deploys (paths-ignore only skips when ALL changed files match).
+    # This pipeline builds + ships the BACKEND /api image to the VPS
+    # only. The frontend deploys independently via Vercel, so a
+    # frontend-only or docs-only commit never needs this pipeline —
+    # skip the GHCR rebuild + VPS container recreate for them. A mixed
+    # commit that also touches backend/src still deploys (paths-ignore
+    # only skips when ALL changed files match).
     paths-ignore:
       - '**/*.md'
       - 'docs/**'
       - 'LICENSE'
+      - 'frontend/**'
 
 env:
   IMAGE: ghcr.io/leanderantony/ai_job_application_agent/api