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>

components/swift/chat/chat-message.tsx

@@ -12,8 +12,10 @@
 
 import { format } from 'date-fns';
 import { nl } from 'date-fns/locale';
+import { CheckCircle2, Sparkles } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import type { ChatMessage as ChatMessageType } from '@/stores/swift-store';
+import { getConfidenceLabel } from '@/lib/swift/action-parser';
 
 // Message styling configuration per type
 const MESSAGE_STYLES = {
@@ -65,6 +67,27 @@ export function ChatMessage({ message, showTimestamp = false }: ChatMessageProps
         {message.content}
       </div>
 
+      {/* Action badge (E3.S4) - show if action was detected */}
+      {message.action && message.type === 'assistant' && (
+        <div className="mt-2 pt-2 border-t border-slate-200">
+          <div className="flex items-center gap-2 text-xs">
+            <Sparkles className="w-3.5 h-3.5 text-amber-600" />
+            <span className="font-medium text-slate-700">
+              {message.action.intent === 'dagnotitie' && 'Dagnotitie'}
+              {message.action.intent === 'zoeken' && 'Patiënt zoeken'}
+              {message.action.intent === 'overdracht' && 'Overdracht'}
+              {message.action.intent === 'unknown' && 'Onbekend'}
+            </span>
+            {message.action.confidence >= 0.7 && (
+              <CheckCircle2 className="w-3.5 h-3.5 text-green-600" />
+            )}
+            <span className="text-slate-500">
+              {getConfidenceLabel(message.action.confidence)}
+            </span>
+          </div>
+        </div>
+      )}
+
       {/* Timestamp (optional) */}
       {showTimestamp && message.timestamp && (
         <div className="text-xs text-slate-400 mt-1.5">