Migrate to MyBatis with proper Controller→Service→Mapper layering

- Add MyBatis Spring Boot Starter with XML mappers and domain classes
- Create 9 mapper interfaces + XML: Restaurant, Video, Channel, Review,
  User, Stats, DaemonConfig, Search, Vector
- Create 10 domain classes with Lombok: Restaurant, VideoSummary,
  VideoDetail, VideoRestaurantLink, Channel, Review, UserInfo,
  DaemonConfig, SiteVisitStats, VectorSearchResult
- Create 7 new service classes: RestaurantService, VideoService,
  ChannelService, ReviewService, UserService, StatsService,
  DaemonConfigService
- Refactor all controllers to be thin (HTTP + auth only), delegating
  business logic to services
- Refactor SearchService, PipelineService, DaemonScheduler, AuthService,
  YouTubeService to use mappers/services instead of JDBC/repositories
- Add Jackson SNAKE_CASE property naming for consistent API responses
- Add ClobTypeHandler for Oracle CLOB→String in MyBatis
- Add IdGenerator utility for centralized UUID generation
- Delete old repository/ package (6 files), JdbcConfig, LowerCaseKeyAdvice
- VectorService retains JDBC for Oracle VECTOR type support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-java/src/main/resources/mybatis/mapper/SearchMapper.xml

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
+<mapper namespace="com.tasteby.mapper.SearchMapper">
+
+    <resultMap id="restaurantMap" type="Restaurant">
+        <id property="id" column="id"/>
+        <result property="name" column="name"/>
+        <result property="address" column="address"/>
+        <result property="region" column="region"/>
+        <result property="latitude" column="latitude"/>
+        <result property="longitude" column="longitude"/>
+        <result property="cuisineType" column="cuisine_type"/>
+        <result property="priceRange" column="price_range"/>
+        <result property="googlePlaceId" column="google_place_id"/>
+        <result property="businessStatus" column="business_status"/>
+        <result property="rating" column="rating"/>
+        <result property="ratingCount" column="rating_count"/>
+    </resultMap>
+
+    <select id="keywordSearch" resultMap="restaurantMap">
+        SELECT DISTINCT r.id, r.name, r.address, r.region, r.latitude, r.longitude,
+               r.cuisine_type, r.price_range, r.google_place_id,
+               r.business_status, r.rating, r.rating_count
+        FROM restaurants r
+        JOIN video_restaurants vr ON vr.restaurant_id = r.id
+        JOIN videos v ON v.id = vr.video_id
+        WHERE r.latitude IS NOT NULL
+          AND (UPPER(r.name) LIKE UPPER(#{query})
+               OR UPPER(r.address) LIKE UPPER(#{query})
+               OR UPPER(r.region) LIKE UPPER(#{query})
+               OR UPPER(r.cuisine_type) LIKE UPPER(#{query})
+               OR UPPER(vr.foods_mentioned) LIKE UPPER(#{query})
+               OR UPPER(v.title) LIKE UPPER(#{query}))
+        FETCH FIRST #{limit} ROWS ONLY
+    </select>
+
+    <select id="findChannelsByRestaurantIds" resultType="map">
+        SELECT DISTINCT vr.restaurant_id, c.channel_name
+        FROM video_restaurants vr
+        JOIN videos v ON v.id = vr.video_id
+        JOIN channels c ON c.id = v.channel_id
+        WHERE vr.restaurant_id IN
+        <foreach item="id" collection="ids" open="(" separator="," close=")">
+            #{id}
+        </foreach>
+    </select>
+
+</mapper>