fix lint errors

frontend/src/App.jsx

@@ -663,7 +663,9 @@ function storedCustomColorPreference() {
   try {
     const local = window.localStorage.getItem(customColorKey)
     if (local && /^#[0-9a-fA-F]{6}$/.test(local)) return local
-  } catch { }
+  } catch {
+    // Ignore unavailable localStorage.
+  }
 
   return ''
 }
@@ -673,13 +675,17 @@ function persistCustomColorPreference(color) {
     writeCookie(customColorCookie, color)
     try {
       window.localStorage.setItem(customColorKey, color)
-    } catch { }
+    } catch {
+      // Ignore unavailable localStorage.
+    }
     return color
   } else {
     writeCookie(customColorCookie, '')
     try {
       window.localStorage.removeItem(customColorKey)
-    } catch { }
+    } catch {
+      // Ignore unavailable localStorage.
+    }
     return ''
   }
 }
@@ -700,7 +706,9 @@ function storedCustomColors() {
         }
         return result
       }
-    } catch { }
+    } catch {
+      // Ignore invalid stored color JSON.
+    }
     return {}
   }
 
@@ -713,7 +721,9 @@ function storedCustomColors() {
   try {
     const local = window.localStorage.getItem(customColorsKey)
     if (local) return parse(local)
-  } catch { }
+  } catch {
+    // Ignore unavailable localStorage.
+  }
 
   return {}
 }
@@ -725,7 +735,11 @@ function persistCustomColors(colors) {
   }
   const json = JSON.stringify(filtered)
   writeCookie(customColorsCookie, json)
-  try { window.localStorage.setItem(customColorsKey, json) } catch { }
+  try {
+    window.localStorage.setItem(customColorsKey, json)
+  } catch {
+    // Ignore unavailable localStorage.
+  }
   return filtered
 }
 
@@ -3453,13 +3467,6 @@ function SettingsPage({ theme, onThemeChange, customColor, onCustomColorChange,
     if (preset.color) setDraftColor(preset.color)
   }
 
-  function handleColorInput(value) {
-    setDraftColor(value)
-    if (/^#[0-9a-fA-F]{6}$/.test(value)) {
-      onCustomColorChange(value)
-    }
-  }
-
   function handleColorPickerChange(value) {
     setDraftColor(value)
     onCustomColorChange(value)