Phase 8: CSV + ICS export, print view, MkDocs docs, SBOM + dev-mode auth

Auth (Test-Mode):
  - middleware.AuthMiddleware now takes a devMode flag. In dev,
    requests without Authorization fall back to a deterministic dev
    UUID (00000000-...-001) and role=teacher. ENVIRONMENT=production
    re-enables the strict 401 path.
  - main.go wires devMode = cfg.Environment != "production".
  - page.tsx replaces the red 'Anmeldung noch nicht integriert' banner
    with a softer Testumgebung notice; the manual-token form moves
    behind a nested details block.

Export endpoints (school-service):
  - LoadExportLessons joins tt_lesson with tt_period for wall-clock
    times; one query feeds both CSV and ICS.
  - WriteCSV streams 10 columns including pinned flag.
  - WriteICS emits one VEVENT per lesson anchored to a Monday — caller
    overridable via ?start=YYYY-MM-DD. RFC 5545 escapes for ',', ';',
    '\n' in icsEscape().
  - NextMonday helper for the default anchor.
  - GET /timetable/solutions/:id/export.{csv,ics} handlers attach
    Content-Disposition: attachment so browsers download instead of
    rendering.

Frontend:
  - lib/stundenplan/api.ts downloadSolutionExport() fetches as blob,
    triggers a synthetic <a download> click, and forwards the JWT when
    present.
  - PlanView gains CSV / ICS / Drucken buttons next to the perspective
    selector. The toolbar carries class 'no-print' so window.print()
    yields only the grid.
  - globals.css @media print rule hides chrome, forces white
    background, gives the table proper borders for A4.

Docs:
  - docs-src/services/stundenplan/{index,architecture,constraints,
    solver-tuning,export}.md with nav entry in mkdocs.yml under
    Services → Stundenplaner.
  - sbom/stundenplan/README.md lists manually-verified key dependencies
    and the policy reference. scripts/stundenplan-sbom.sh generates
    full machine-readable inventories via go-licenses + pip-licenses
    + license-checker when those tools are available.

Tests:
  - internal/services/timetable_exports_test.go: 4 unit tests covering
    CSV column layout + quoting, ICS structure + DTSTART formatting,
    icsEscape special chars, NextMonday weekday math.
  - studio-v2/e2e/stundenplan-export.spec.ts split out of the main spec
    file (LOC budget) — 3 tests for button render, CSV download,
    ICS download.
  - mockSchoolApi extended with export.csv + export.ics routes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

studio-v2/app/stundenplan/_components/plan/PlanView.tsx

@@ -2,7 +2,7 @@
 
 import { useState, useEffect, useCallback, useMemo } from 'react'
 import { useTheme } from '@/lib/ThemeContext'
-import { solutionsApi, subjectsApi, lessonsApi } from '@/lib/stundenplan/api'
+import { solutionsApi, subjectsApi, lessonsApi, downloadSolutionExport } from '@/lib/stundenplan/api'
 import type { TimetableLesson, TimetableSubject } from '@/app/stundenplan/types'
 
 interface PlanViewProps {
@@ -125,9 +125,15 @@ export function PlanView({ solutionId }: PlanViewProps) {
   const cardClass = isDark ? 'bg-white/10 border-white/20 text-white' : 'bg-white/80 border-black/10 text-slate-900'
   const selectClass = isDark ? 'bg-white/10 border-white/20 text-white' : 'bg-white border-slate-300 text-slate-900'
 
+  const handleExport = (fmt: 'csv' | 'ics') => {
+    downloadSolutionExport(solutionId, fmt).catch(e =>
+      setError(e instanceof Error ? e.message : 'Export fehlgeschlagen'),
+    )
+  }
+
   return (
     <div className="space-y-4" data-testid="plan-view">
-      <div className={`p-4 rounded-2xl border backdrop-blur-xl ${cardClass}`}>
+      <div className={`p-4 rounded-2xl border backdrop-blur-xl no-print ${cardClass}`}>
         <div className="flex flex-wrap items-center gap-3">
           <div>
             <label className="block text-xs mb-1 opacity-70">Perspektive</label>
@@ -155,6 +161,32 @@ export function PlanView({ solutionId }: PlanViewProps) {
               {resources.map(r => <option key={r.id} value={r.id}>{r.label}</option>)}
             </select>
           </div>
+          <div>
+            <label className="block text-xs mb-1 opacity-70">Export</label>
+            <div className="flex gap-1">
+              <button
+                onClick={() => handleExport('csv')}
+                data-testid="export-csv"
+                className={`px-3 py-1.5 rounded-lg text-sm font-medium transition-colors ${isDark ? 'bg-white/10 text-white/80 hover:bg-white/20' : 'bg-slate-100 text-slate-700 hover:bg-slate-200'}`}
+              >
+                CSV
+              </button>
+              <button
+                onClick={() => handleExport('ics')}
+                data-testid="export-ics"
+                className={`px-3 py-1.5 rounded-lg text-sm font-medium transition-colors ${isDark ? 'bg-white/10 text-white/80 hover:bg-white/20' : 'bg-slate-100 text-slate-700 hover:bg-slate-200'}`}
+              >
+                ICS
+              </button>
+              <button
+                onClick={() => window.print()}
+                data-testid="export-print"
+                className={`px-3 py-1.5 rounded-lg text-sm font-medium transition-colors ${isDark ? 'bg-white/10 text-white/80 hover:bg-white/20' : 'bg-slate-100 text-slate-700 hover:bg-slate-200'}`}
+              >
+                Drucken
+              </button>
+            </div>
+          </div>
         </div>
       </div>