feat(htykc): add course_package CRUD with pagination and org scoping

Introduce course_package table and API for selling course templates.
Supports teacher-owned and org-wide active package queries with keyword
search, sort order, and pagination.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

htykc_models/migrations/2026-04-30-100000_create_course_package/up.sql

@@ -0,0 +1,23 @@
+-- 课包（用于卖课的产品模板）
+CREATE TABLE course_package (
+    id VARCHAR NOT NULL PRIMARY KEY,
+    package_name VARCHAR NOT NULL,
+    description TEXT,
+    ws_course_id VARCHAR,
+    total_lessons INT4 DEFAULT 0,
+    original_price INT8 DEFAULT 0,
+    selling_price INT8 DEFAULT 0,
+    validity_days INT4 DEFAULT 0,
+    package_status VARCHAR NOT NULL DEFAULT 'ACTIVE',
+    cover_image_url VARCHAR,
+    sort_order INT4 DEFAULT 0,
+    created_by VARCHAR,
+    created_at TIMESTAMP NOT NULL DEFAULT NOW(),
+    updated_at TIMESTAMP,
+    is_delete BOOL DEFAULT FALSE,
+    org_id VARCHAR
+);
+
+CREATE INDEX idx_course_package_org_id ON course_package (org_id);
+CREATE INDEX idx_course_package_created_by ON course_package (created_by);
+CREATE INDEX idx_course_package_status ON course_package (package_status);