fix: handle invalid weather API key gracefully and fix TideDisplay crash

- Fix TideDisplay component crash (use extremes instead of tides)
- Handle 401 weather API errors gracefully (return null data with note)
- Update weather controller to return 200 with null values instead of 503
- Add helpful message about API key activation time
- Fix tide type capitalization (High/Low instead of high/low)

src/components/external/TideDisplay.tsx

@@ -84,13 +84,13 @@ export function TideDisplay({ latitude, longitude }: TideDisplayProps) {
 
       <div className="space-y-2">
         <div className="text-sm font-medium text-gray-700 mb-2">Today's Tides</div>
-        {tideData.tides.slice(0, 4).map((tide, index) => (
+        {tideData.extremes && tideData.extremes.slice(0, 4).map((tide, index) => (
           <div
             key={index}
             className="flex items-center justify-between py-2 border-b border-gray-100 last:border-0"
           >
             <div className="flex items-center space-x-3">
-              <span className="text-lg">{tide.type === 'high' ? '⬆️' : '⬇️'}</span>
+              <span className="text-lg">{tide.type === 'High' ? '⬆️' : '⬇️'}</span>
               <div>
                 <div className="font-medium capitalize">{tide.type} Tide</div>
                 <div className="text-xs text-gray-500">