feat: add LTI 1.3 Tool Consumer support with database migrations and API endpoints

- Implemented database migrations for lti_external_tools and lti_grade_passback_events tables in both cms-service and lms-service.
- Created API handlers for managing LTI tools including listing, creating, updating, and deleting tools.
- Added functionality for LTI grade passback with validation and signature verification.
- Developed frontend components for LTI tool management and display in course editor.

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

services/lms-service/migrations/20260427000004_lti_tool_consumer.sql

@@ -0,0 +1,40 @@
+-- Fase 36: LTI 1.3 Tool Consumer
+-- Registro de herramientas externas por curso + eventos de passback de notas
+
+CREATE TABLE IF NOT EXISTS lti_external_tools (
+    id              UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    organization_id UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    course_id       UUID NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
+    name            TEXT NOT NULL,
+    launch_url      TEXT NOT NULL,
+    shared_secret   TEXT NOT NULL,
+    enabled         BOOLEAN NOT NULL DEFAULT TRUE,
+    config          JSONB NOT NULL DEFAULT '{}',
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    updated_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (organization_id, course_id, name)
+);
+
+CREATE INDEX IF NOT EXISTS idx_lti_external_tools_org_course
+    ON lti_external_tools(organization_id, course_id);
+
+CREATE TABLE IF NOT EXISTS lti_grade_passback_events (
+    id               UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    organization_id  UUID NOT NULL REFERENCES organizations(id) ON DELETE CASCADE,
+    tool_id          UUID NOT NULL REFERENCES lti_external_tools(id) ON DELETE CASCADE,
+    user_id          UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    course_id        UUID NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
+    lesson_id        UUID REFERENCES lessons(id) ON DELETE SET NULL,
+    raw_score        FLOAT4 NOT NULL,
+    max_score        FLOAT4 NOT NULL DEFAULT 1,
+    normalized_score FLOAT4 NOT NULL,
+    status           TEXT,
+    metadata         JSONB NOT NULL DEFAULT '{}',
+    created_at       TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_lti_passback_tool_created
+    ON lti_grade_passback_events(tool_id, created_at DESC);
+
+CREATE INDEX IF NOT EXISTS idx_lti_passback_user_course
+    ON lti_grade_passback_events(user_id, course_id);