feat(cortex): Epic 0 - Foundation & Context voor V2 architectuur

Implementeert de basis voor de Cortex V2 three-layer architecture.

E0.S1 - CortexContext Types (lib/cortex/types.ts):
- EscalationReason type voor Reflex → Orchestrator
- LocalClassificationResult met ambiguity detection
- CortexContext voor AI classificatie context
- IntentChain en IntentAction voor multi-intent flows
- NudgeSuggestion voor proactieve suggesties
- CONFIDENCE_THRESHOLD (0.7) en AMBIGUITY_THRESHOLD (0.1)
- getCurrentShift() utility (DRY - herbruikbaar)

E0.S2 - Context API (app/api/cortex/context/route.ts):
- GET endpoint voor huidige context
- Haalt agenda vandaag op uit database
- Retourneert CortexContext object

E0.S3 - Feature Flags (lib/config/feature-flags.ts):
- CORTEX_V2_ENABLED, CORTEX_MULTI_INTENT
- CORTEX_NUDGE, CORTEX_LOGGING
- isFeatureEnabled() helper
- Dev mode: default true

E0.S4 - CortexStore V2 (stores/cortex-store.ts):
- Types geïmporteerd uit lib/cortex (DRY)
- ChatEntities type voor AI responses (string-based)
- V2 state: context, activeChain, chainHistory, suggestions
- V2 actions: chain management, nudge management, clarification

E0.S5 - Classification Logging (lib/cortex/logger.ts):
- PII sanitization (BSN, tel, namen, email)
- logClassification(), logEscalation(), logNudge()
- logPerformance() met threshold checks

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

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

lib/config/feature-flags.ts

@@ -0,0 +1,46 @@
+/**
+ * Feature Flags for Cortex V2
+ *
+ * Controls gradual rollout of new features.
+ * In development, all flags default to true for testing.
+ */
+
+/** Feature flag definitions */
+export const FEATURE_FLAGS = {
+  /** Enable Cortex V2 architecture (Reflex + Orchestrator) */
+  CORTEX_V2_ENABLED: process.env.NEXT_PUBLIC_CORTEX_V2 === 'true',
+
+  /** Enable multi-intent detection and ActionChainCard */
+  CORTEX_MULTI_INTENT: process.env.NEXT_PUBLIC_CORTEX_MULTI_INTENT === 'true',
+
+  /** Enable proactive nudge suggestions */
+  CORTEX_NUDGE: process.env.NEXT_PUBLIC_CORTEX_NUDGE === 'true',
+
+  /** Enable classification logging (dev only) */
+  CORTEX_LOGGING: process.env.NEXT_PUBLIC_CORTEX_LOGGING === 'true',
+} as const;
+
+/** Type for feature flag keys */
+export type FeatureFlagKey = keyof typeof FEATURE_FLAGS;
+
+/**
+ * Check if a feature flag is enabled
+ */
+export function isFeatureEnabled(flag: FeatureFlagKey): boolean {
+  // In development, default to true if env var not set
+  if (process.env.NODE_ENV === 'development') {
+    const envValue = process.env[`NEXT_PUBLIC_${flag}`];
+    // Only return false if explicitly set to 'false'
+    return envValue !== 'false';
+  }
+  return FEATURE_FLAGS[flag];
+}
+
+/**
+ * Get all enabled features (useful for debugging)
+ */
+export function getEnabledFeatures(): FeatureFlagKey[] {
+  return (Object.keys(FEATURE_FLAGS) as FeatureFlagKey[]).filter(
+    (flag) => isFeatureEnabled(flag)
+  );
+}