fix: SuggestionsModal now fetches fresh suggestions every time

Bug: SuggestionsModal only fetched on first open because it checked
if suggestions.length === 0 before fetching. This meant changing the
prompt and re-opening the modal showed stale suggestions.

Fix: useEffect now:
- Clears suggestions and error on every open
- Always fetches fresh suggestions when isOpen changes
- Also re-fetches when userInput changes while modal is open
- Dependency array: [isOpen, userInput]

Result: Every click of 'Get Suggestions' generates new, relevant
suggestions based on the current prompt.

frontend/src/components/SuggestionsModal.tsx

@@ -35,12 +35,14 @@ export default function SuggestionsModal({ isOpen, onClose, onSelect, userInput
     }
   }
 
-  // Auto-fetch when opened
+  // Auto-fetch when opened — always fetch fresh suggestions
   useEffect(() => {
-    if (isOpen && suggestions.length === 0 && !loading && !error) {
+    if (isOpen) {
+      setSuggestions([])
+      setError('')
       fetchSuggestions()
     }
-  }, [isOpen])
+  }, [isOpen, userInput])
 
   if (!isOpen) return null