[FEAT] Add onboarding wizard with visura camerale and CertiSource integration

- New 5-step onboarding wizard (onboarding.html) replacing setup-org.html
- Step 1: Choose data source (Upload Visura / CertiSource / Manual)
- Step 2: PDF upload with AI extraction or CertiSource P.IVA lookup
- Step 3: Verify/complete company data with NIS2 sector mapping
- Step 4: User profile completion
- Step 5: NIS2 classification (Essential/Important) with summary
- OnboardingController with upload-visura, fetch-company, complete endpoints
- VisuraService with Claude AI PDF extraction and ATECO-to-NIS2 mapping
- CertiSource API integration for automatic company data retrieval
- Updated login/register redirects to point to new onboarding wizard

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/js/api.js

@@ -238,6 +238,30 @@ class NIS2API {
     generateComplianceReport() { return this.get('/audit/report'); }
     getAuditLogs(params = {}) { return this.get('/audit/logs?' + new URLSearchParams(params)); }
     getIsoMapping() { return this.get('/audit/iso27001-mapping'); }
+
+    // ═══════════════════════════════════════════════════════════════════
+    // Onboarding
+    // ═══════════════════════════════════════════════════════════════════
+
+    async uploadVisura(file) {
+        const formData = new FormData();
+        formData.append('visura', file);
+        const headers = { 'Authorization': 'Bearer ' + this.token };
+        if (this.orgId) headers['X-Organization-Id'] = this.orgId;
+        try {
+            const response = await fetch(this.baseUrl + '/onboarding/upload-visura', {
+                method: 'POST',
+                headers,
+                body: formData,
+            });
+            return response.json();
+        } catch (error) {
+            return { success: false, message: 'Errore di connessione al server' };
+        }
+    }
+
+    fetchCompany(vatNumber) { return this.post('/onboarding/fetch-company', { vat_number: vatNumber }); }
+    completeOnboarding(data) { return this.post('/onboarding/complete', data); }
 }
 
 // Singleton globale