fix: ESLint errors and update git hooks to include ESLint

- HostDetailPage.tsx: fix eqeqeq (!= to !==)
- HostsPage.tsx: merge duplicate @mui/icons-material imports
- PatchDeploymentPage.tsx: merge duplicate @mui/icons-material imports
- pre-commit hook: add ESLint check
- pre-push hook: add ESLint check

scripts/git-hooks/pre-push

@@ -2,7 +2,7 @@
 # =============================================================================
 # Linux Patch Manager — Pre-Push Hook
 # =============================================================================
-# Safety net: verifies cargo fmt and frontend build pass before pushing.
+# Safety net: verifies cargo fmt, ESLint, and TypeScript pass before pushing.
 # Install: ./scripts/git-hooks/install.sh
 # =============================================================================
 
@@ -20,6 +20,15 @@ if [[ -f "${REPO_ROOT}/Cargo.toml" ]]; then
     fi
 fi
 
+# ── Frontend ESLint ──────────────────────────────────────────────────────────
+if [[ -f "${REPO_ROOT}/frontend/package.json" ]]; then
+    echo "[pre-push] Running ESLint ..."
+    if ! (cd "${REPO_ROOT}/frontend" && npx eslint src/ --ext .ts,.tsx --max-warnings 0 2>/dev/null); then
+        echo "[pre-push] ❌ ESLint check FAILED."
+        FAILED=1
+    fi
+fi
+
 # ── Frontend type check ─────────────────────────────────────────────────────
 if [[ -f "${REPO_ROOT}/frontend/package.json" ]]; then
     echo "[pre-push] Checking TypeScript types ..."