Phase 6: Plan-Ansicht — solution list + weekly grid view

Frontend additions in studio-v2:
  - types.ts adds TimetableSolution, TimetableLesson, SolutionStatus,
    CreateTimetableSolution mirroring the Go models.
  - lib/stundenplan/api.ts adds solutionsApi with list/get/create/remove/
    lessons. Solve trigger is POST /timetable/solutions — school-service
    forwards to the solver-service over the Docker network.
  - _components/plan/SolutionList: table of past solves with status
    badges, hard/soft score, Anzeigen + Loeschen buttons, and a
    'Neuen Plan generieren' trigger. Auto-polls every 4 s while any
    solution is pending/running, clears the interval otherwise.
  - _components/plan/PlanView: Mo–Fr × period weekly grid. Three
    perspectives (Klasse / Lehrer / Raum) toggleable via test-id'd
    buttons; selector below lists every unique resource with at least
    one lesson. Cells colour-coded by tt_subject.color.
  - _components/plan/PlanHub orchestrates list + view; default tab in
    page.tsx switches from 'klassen' to 'plan'.

Tests:
  - mockSchoolApi helper extracted to e2e/_helpers.ts so the spec file
    stays under 500 LOC. Helper now also mocks /solutions GET/POST/DELETE
    and /solutions/:id/lessons; solutions kept in a closure so POST
    appears in the next GET.
  - 8 new tests across two suites: SolutionList empty state, list
    render, completed-vs-failed Anzeigen visibility, solve trigger;
    PlanView placeholder when no selection, grid render, perspective
    switching.
  - Existing Klassen CRUD tests now click the Klassen tab first
    (Plan is the new default landing tab).

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

studio-v2/lib/stundenplan/api.ts

@@ -16,6 +16,7 @@ import type {
   SubjectPreferredPeriod, SubjectDoubleLesson,
   ClassMaxHoursDay, ClassNoGaps,
   RoomRequiresType, RoomUnavailable,
+  TimetableSolution, TimetableLesson, CreateTimetableSolution,
 } from '@/app/stundenplan/types'
 
 const TOKEN_KEY = 'bp_stundenplan_jwt'
@@ -138,3 +139,16 @@ export const classNoGapsApi = constraintApi<ClassNoGaps, Omit<ClassNoGaps, 'id'
 
 export const roomRequiresTypeApi = constraintApi<RoomRequiresType, Omit<RoomRequiresType, 'id' | 'created_by_user_id' | 'created_at'>>('room/requires-type')
 export const roomUnavailableApi = constraintApi<RoomUnavailable, Omit<RoomUnavailable, 'id' | 'created_by_user_id' | 'created_at'>>('room/unavailable')
+
+// ---------- Solutions ----------
+
+export const solutionsApi = {
+  list: () => apiFetch<TimetableSolution[]>('/timetable/solutions'),
+  get: (id: string) => apiFetch<TimetableSolution>(`/timetable/solutions/${id}`),
+  create: (data: CreateTimetableSolution) =>
+    apiFetch<TimetableSolution>('/timetable/solutions', { method: 'POST', body: JSON.stringify(data) }),
+  remove: (id: string) =>
+    apiFetch<void>(`/timetable/solutions/${id}`, { method: 'DELETE' }),
+  lessons: (id: string) =>
+    apiFetch<TimetableLesson[]>(`/timetable/solutions/${id}/lessons`),
+}