ci(smoke): add comment explaining why --with-deps is omitted

OS deps are pre-installed on the self-hosted peptide-vps runner host.
--with-deps invokes apt-get which fails under the runner's NoNewPrivileges
sandbox hardening. Flag was already dropped in e00f777; this adds an
inline comment so the intent is self-documenting for future maintainers.

Agent-Session: smoke-no-withdeps-20260617

.github/workflows/smoke.yml

@@ -53,6 +53,7 @@ jobs:
         run: npm ci
 
       - name: Install Playwright browsers
+        # OS deps pre-installed on the self-hosted runner host; --with-deps needs sudo which the sandbox blocks
         run: npx playwright install chromium
 
       - name: Run smoke tests