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

frontend/src/pages/HostDetailPage.tsx

@@ -1071,7 +1071,7 @@ export default function HostDetailPage() {
                     </Typography>
                   </TableCell>
                   <TableCell>
-                    {check.last_result?.latency_ms != null ? `${check.last_result.latency_ms} ms` : '—'}
+                    {check.last_result?.latency_ms !== null && check.last_result?.latency_ms !== undefined ? `${check.last_result.latency_ms} ms` : '—'}
                   </TableCell>
                   <TableCell>
                     {check.last_result?.checked_at

frontend/src/pages/HostsPage.tsx

@@ -4,8 +4,7 @@ import {
   Paper, Table, TableBody, TableCell, TableContainer, TableHead,
   TableRow, TextField, Toolbar, Tooltip, Typography,
 } from '@mui/material'
-import { Add as AddIcon, Refresh as RefreshIcon, Delete as DeleteIcon } from '@mui/icons-material'
-import { CheckCircle as CheckCircleIcon, Cancel as CancelIcon, Remove as RemoveIcon } from '@mui/icons-material'
+import { Add as AddIcon, Refresh as RefreshIcon, Delete as DeleteIcon, CheckCircle as CheckCircleIcon, Cancel as CancelIcon, Remove as RemoveIcon } from '@mui/icons-material'
 import { useNavigate } from 'react-router-dom'
 import { apiClient, hostsApi } from '../api/client'
 import type { Host, HostHealthStatus } from '../types'

frontend/src/pages/PatchDeploymentPage.tsx

@@ -24,8 +24,7 @@ import {
   Typography,
   Tooltip,
 } from '@mui/material'
-import { Search as SearchIcon } from '@mui/icons-material'
-import { CheckCircle as CheckCircleIcon, Cancel as CancelIcon, Remove as RemoveIcon } from '@mui/icons-material'
+import { Search as SearchIcon, CheckCircle as CheckCircleIcon, Cancel as CancelIcon, Remove as RemoveIcon } from '@mui/icons-material'
 import { useNavigate } from 'react-router-dom'
 import { hostsApi, jobsApi } from '../api/client'
 import type { Host, HostHealthStatus } from '../types'

scripts/git-hooks/pre-commit

@@ -2,8 +2,8 @@
 # =============================================================================
 # Linux Patch Manager — Pre-Commit Hook
 # =============================================================================
-# Auto-formats Rust code and runs frontend type check before each commit.
-# Prevents CI format-check failures by ensuring code is always formatted.
+# Auto-formats Rust code and runs frontend checks before each commit.
+# Prevents CI format-check and lint failures by catching issues locally.
 # Install: ./scripts/git-hooks/install.sh
 # =============================================================================
 
@@ -16,17 +16,20 @@ if [[ -f "${REPO_ROOT}/Cargo.toml" ]]; then
     echo "[pre-commit] Running cargo fmt --all ..."
     cargo fmt --all --manifest-path "${REPO_ROOT}/Cargo.toml" 2>/dev/null
 
-    # Re-stage any files that cargo fmt reformatted (including previously unstaged)
+    # Re-stage any files that cargo fmt reformatted
     STAGED_RS=$(git diff --name-only --diff-filter=ACM -- '*.rs')
     if [[ -n "${STAGED_RS}" ]]; then
         git add ${STAGED_RS}
     fi
 fi
 
-# ── Frontend type check ─────────────────────────────────────────────────────
+# ── Frontend checks ──────────────────────────────────────────────────────────
 if [[ -f "${REPO_ROOT}/frontend/package.json" ]]; then
-    echo "[pre-commit] Running TypeScript type check ..."
+    echo "[pre-commit] Running ESLint ..."
     cd "${REPO_ROOT}/frontend"
+    npx eslint src/ --ext .ts,.tsx --max-warnings 0 2>/dev/null
+
+    echo "[pre-commit] Running TypeScript type check ..."
     npx tsc --noEmit 2>/dev/null
 fi
 

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 ..."