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/command-center/command-center.tsx

@@ -1,25 +1,27 @@
 'use client';
 
 /**
- * Command Center
+ * Command Center (v3.0)
  *
  * Main container for the Swift interface.
- * 4-zone layout: Context Bar | Canvas Area | Recent Strip | Command Input
+ * Split-screen layout: Chat Panel (40%) | Artifact Area (60%)
  *
  * Layout specs:
- * - Context Bar: 48px (h-12)
- * - Canvas Area: flex-1 (fills remaining space)
- * - Recent Strip: 48px (h-12)
- * - Command Input: 64px (h-16)
+ * - Context Bar: 48px (h-12) - UNCHANGED
+ * - Split container: flex-1 (fills remaining space)
+ *   - Chat Panel: 40% width (desktop), 100% (mobile)
+ *   - Artifact Area: 60% width (desktop), 100% (mobile)
+ *
+ * Epic: E1 (Foundation)
+ * Stories: E1.S2 (Split-screen layout), E1.S3 (Placeholders), E1.S4 (Responsive)
  */
 
 import { useEffect, useCallback, useRef } from 'react';
 import { useSwiftStore } from '@/stores/swift-store';
 import { ContextBar } from './context-bar';
-import { CommandInput } from './command-input';
-import { RecentStrip } from './recent-strip';
-import { CanvasArea } from './canvas-area';
 import { OfflineBanner } from './offline-banner';
+import { ChatPanel } from '../chat/chat-panel';
+import { ArtifactArea } from '../artifacts/artifact-area';
 
 export function CommandCenter() {
   const { closeBlock, activeBlock } = useSwiftStore();
@@ -34,7 +36,7 @@ export function CommandCenter() {
         closeBlock();
       }
 
-      // Cmd/Ctrl + K: focus input
+      // Cmd/Ctrl + K: focus input (chat input in v3.0)
       if ((e.metaKey || e.ctrlKey) && e.key === 'k') {
         e.preventDefault();
         inputRef.current?.focus();
@@ -49,21 +51,25 @@ export function CommandCenter() {
   }, [handleKeyDown]);
 
   return (
-    <>
+    <div className="flex flex-col h-screen overflow-hidden">
       {/* Offline Banner */}
       <OfflineBanner />
 
-      {/* Context Bar - 48px */}
+      {/* Context Bar - 48px (unchanged) */}
       <ContextBar />
 
-      {/* Canvas Area - flex */}
-      <CanvasArea />
+      {/* Split-screen container - flex-1 */}
+      <div className="flex-1 flex overflow-hidden">
+        {/* Chat Panel - 40% (desktop), 100% (mobile) */}
+        <div className="w-full lg:w-[40%] border-r border-slate-200 flex flex-col">
+          <ChatPanel />
+        </div>
 
-      {/* Recent Strip - 48px */}
-      <RecentStrip />
-
-      {/* Command Input - 64px */}
-      <CommandInput ref={inputRef} />
-    </>
+        {/* Artifact Area - 60% (desktop), hidden on mobile */}
+        <div className="hidden lg:flex lg:w-[60%] flex-col">
+          <ArtifactArea />
+        </div>
+      </div>
+    </div>
   );
 }