feat(swift): implementeer intent detection & action parsing (E3.S4)

Epic 3 Story 4 compleet: AI action objects worden geparsed en gevalideerd.

E3.S4 - Intent Detection in Response (5 SP)
- Action parser met JSON extraction uit markdown code blocks
- Zod validatie voor action schema (intent, entities, confidence, artifact)
- Confidence-based artifact opening (≥0.7 threshold)
- Visual feedback met action badges in chat messages
- Console logging voor debugging

Nieuwe Components:
- lib/swift/action-parser.ts (149 regels)
  - parseActionFromResponse(): Extract & validate JSON actions
  - extractJsonBlock(): Regex matching voor ```json blocks
  - removeJsonBlocks(): Clean text zonder JSON
  - shouldOpenArtifact(): Confidence check (≥0.7)
  - getConfidenceLabel(): "Zeer zeker", "Redelijk zeker", etc.
  - validateArtifactType(): Intent/artifact type matching

Components Updated:
- components/swift/chat/chat-panel.tsx
  - Action parsing in onDone callback
  - setPendingAction voor artifact opening (E3.S6)
  - Console logging: "[ChatPanel] Action detected"

- components/swift/chat/chat-message.tsx
  - Action badge met Sparkles icon
  - Intent label (Dagnotitie, Patiënt zoeken, Overdracht)
  - CheckCircle icon voor high confidence (≥0.7)
  - Confidence label display

- stores/swift-store.ts
  - updateLastMessage(): Optional action parameter
  - Type-safe action assignment (null/undefined handling)

Features:
- JSON extraction via regex: /```json\s*\n([\s\S]*?)\n```/
- Zod schema: type, intent, entities, confidence, artifact
- Confidence thresholds: >0.9, 0.7-0.9, 0.5-0.7, <0.5
- Visual feedback: Sparkles + CheckCircle icons
- Cleaned text content (JSON removed from display)
- Action stored in message.action en pendingAction state

Action Schema:
```typescript
{
  type: "action",
  intent: "dagnotitie" | "zoeken" | "overdracht" | "unknown",
  entities: {
    patientName?: string,
    patientId?: string,
    category?: "medicatie" | "adl" | "gedrag" | "incident" | "observatie",
    content?: string,
    query?: string
  },
  confidence: number, // 0-1
  artifact?: {
    type: BlockType,
    prefill: Record<string, any>
  }
}
```

Build Status:
- ✅ pnpm build succesvol (geen type errors)
- Alleen bekende warnings (Supabase realtime, useCallback)

Voortgang: 46 SP / 85 SP (54%) - E3.S4 compleet

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

stores/swift-store.ts

@@ -102,7 +102,7 @@ interface SwiftStore {
 
   // Chat actions (v3.0)
   addChatMessage: (message: Omit<ChatMessage, 'id' | 'timestamp'>) => void;
-  updateLastMessage: (content: string) => void;
+  updateLastMessage: (content: string, action?: ChatAction | null) => void;
   clearChat: () => void;
   setStreaming: (streaming: boolean) => void;
   setPendingAction: (action: ChatAction | null) => void;
@@ -215,15 +215,22 @@ export const useSwiftStore = create<SwiftStore>()(
         );
       },
 
-      updateLastMessage: (content) => {
+      updateLastMessage: (content, action?) => {
         set(
           (state) => {
             const messages = [...state.chatMessages];
             if (messages.length > 0) {
-              messages[messages.length - 1] = {
+              const updatedMessage: ChatMessage = {
                 ...messages[messages.length - 1],
                 content,
               };
+
+              // Only add action if it's not null/undefined
+              if (action !== undefined && action !== null) {
+                updatedMessage.action = action;
+              }
+
+              messages[messages.length - 1] = updatedMessage;
             }
             return { chatMessages: messages };
           },