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>