feat: complete exam lifecycle — AI generation, submission, student session, and results

- Backend: AI generation fallbacks when OpenAI not configured, full exam
  submission saving all params (difficulty, rubric, entity, grading system,
  approval workflow) and creating linked question records per section
- Backend: new exam session controller with get_session, autosave, submit,
  status, and results endpoints; student attempt/answer/score models
- Backend: new controllers for entities, approval workflows, exam schedules
- Frontend: exam session split-layout with passage panel, question types
  (MCQ, T/F/NG, gap-fill, writing, speaking), timer, and review dialog
- Frontend: results page with percentage score, per-answer breakdown table
- Frontend: generation page dynamic dropdowns, full payload submission
- Frontend: updated types for ExamSessionSection, ExamQuestion options

Made-with: Cursor

custom_addons/encoach_core/data/encoach_permissions.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <odoo>
-    <data noupdate="0">
+    <data noupdate="1">
         <!-- Global permissions (PermissionType from permissions.ts) -->
         <record id="perm_viewCorporate" model="encoach.permission">
             <field name="code">viewCorporate</field>