feat: initial backend codebase — EnCoach v3

Complete Odoo 19 backend with 25 custom addons:
- encoach_core: user/entity/role management
- encoach_api: REST API + JWT auth
- encoach_ai: OpenAI integration, AI settings, generation
- encoach_ai_course: AI-powered English & IELTS course generation
- encoach_exam_template/session: exam creation, structures, sessions
- encoach_scoring: AI auto-grading + manual approval
- encoach_vector: pgvector RAG integration
- encoach_adaptive: adaptive learning engine
- encoach_placement: placement testing
- encoach_taxonomy/resources: content taxonomy & resource management
- Plus 14 more modules for courses, branding, portal, etc.

Includes docs: user guide, generation report, developer workflow.

Made-with: Cursor

custom_addons/encoach_vector/data/vector_defaults.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <!-- Scheduled action: re-index vectors daily -->
+    <record id="ir_cron_vector_reindex" model="ir.cron">
+        <field name="name">EnCoach: Vector Re-Index</field>
+        <field name="model_id" ref="model_encoach_embedding"/>
+        <field name="state">code</field>
+        <field name="code">model.cron_reindex()</field>
+        <field name="interval_number">1</field>
+        <field name="interval_type">days</field>
+        <field name="active">True</field>
+    </record>
+</odoo>