feat: add mentorship assignments and peer review enhancements

- Create `mentorship_assignments` table with relevant fields and indexes.
- Add `peer_review_settings` table for lesson-specific peer review configurations.
- Enhance `peer_reviews` and `course_submissions` tables with additional fields for instructor reviews and final scores.
- Implement My Notes page to display user annotations with delete functionality.
- Create Lesson Annotations component for managing notes with editing and deletion capabilities.
- Develop Mentor Panel component to display mentor and mentee information.
- Add Course Mentorships page for assigning mentors to students with modal for selection.

Co-authored-by: Copilot <copilot@github.com>

services/lms-service/migrations/20260428000001_lesson_annotations.sql

@@ -0,0 +1,19 @@
+-- Fase 41-B: Anotaciones Privadas en Lecciones
+CREATE TABLE IF NOT EXISTS lesson_annotations (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id         UUID NOT NULL,
+    lesson_id       UUID NOT NULL,
+    organization_id UUID NOT NULL,
+    course_id       UUID NOT NULL,
+    content         TEXT NOT NULL,
+    -- JSON libre: { "type": "timestamp", "value": 42.5 } | { "type": "scroll", "value": 0.35 }
+    position_data   JSONB,
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at      TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_lesson_annotations_user_lesson
+    ON lesson_annotations (user_id, lesson_id);
+
+CREATE INDEX IF NOT EXISTS idx_lesson_annotations_user_org
+    ON lesson_annotations (user_id, organization_id);