feat: add reporting frontend, fix module categorization, update docs

- Create Reporting module frontend (page.tsx) with executive dashboard
  showing compliance score, risk overview, deadlines, module KPIs
- Create Reporting lib (types.ts, api.ts) matching Go backend models
- Add Reporting to STEP_EXPLANATIONS and both SDK sidebars
- Remove DSB Portal, Multi-Tenant, SSO from SDK sidebars (admin-only)
- Add Multi-Tenant, SSO, DSB Portal to dashboard navigation.ts
  with 'Plattform-Verwaltung' subgroup
- Update docs: academy.md (PDF certs), reporting.md (new),
  index.md (SDK vs Admin categorization), mkdocs.yml (all modules)

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

admin-compliance/lib/sdk/reporting/api.ts

@@ -0,0 +1,65 @@
+/**
+ * Reporting API Client
+ *
+ * Client functions for the Executive Reporting module.
+ * Communicates with the Go backend via Next.js API proxy at /api/sdk/v1/reporting/*
+ */
+
+import type {
+  ExecutiveReport,
+  ComplianceScoreResponse,
+  Deadline,
+  RiskOverview,
+} from './types'
+
+const BASE_URL = '/api/sdk/v1/reporting'
+
+async function apiFetch<T>(path: string): Promise<T> {
+  const res = await fetch(`${BASE_URL}${path}`, {
+    headers: {
+      'Content-Type': 'application/json',
+      'X-Tenant-ID': typeof window !== 'undefined'
+        ? (localStorage.getItem('bp-tenant-id') || 'default')
+        : 'default',
+    },
+  })
+
+  if (!res.ok) {
+    const error = await res.json().catch(() => ({ error: res.statusText }))
+    throw new Error(error.error || `API Error: ${res.status}`)
+  }
+
+  return res.json()
+}
+
+/**
+ * Vollstaendigen Executive Report abrufen
+ * GET /sdk/v1/reporting/executive
+ */
+export async function getExecutiveReport(): Promise<ExecutiveReport> {
+  return apiFetch<ExecutiveReport>('/executive')
+}
+
+/**
+ * Nur den Compliance-Score abrufen (leichtgewichtig)
+ * GET /sdk/v1/reporting/score
+ */
+export async function getComplianceScore(): Promise<ComplianceScoreResponse> {
+  return apiFetch<ComplianceScoreResponse>('/score')
+}
+
+/**
+ * Bevorstehende Fristen abrufen
+ * GET /sdk/v1/reporting/deadlines
+ */
+export async function getUpcomingDeadlines(): Promise<{ deadlines: Deadline[]; total: number }> {
+  return apiFetch<{ deadlines: Deadline[]; total: number }>('/deadlines')
+}
+
+/**
+ * Risikouebersicht abrufen
+ * GET /sdk/v1/reporting/risks
+ */
+export async function getRiskOverview(): Promise<RiskOverview> {
+  return apiFetch<RiskOverview>('/risks')
+}