Migrate backend from Python to Java Spring Boot

- Full Java 21 + Spring Boot 3.3 backend with Virtual Threads
- HikariCP connection pool for Oracle ADB
- JWT auth, Redis caching, OCI GenAI integration
- YouTube transcript extraction via API + Playwright browser fallback
- SSE streaming for bulk operations
- Scheduled daemon for channel scanning/video processing
- Mobile UI: collapse restaurant list to single row on selection
- Switch PM2 ecosystem config to Java backend

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

backend-java/src/main/resources/application.yml

@@ -0,0 +1,63 @@
+server:
+  port: 8000
+
+spring:
+  threads:
+    virtual:
+      enabled: true
+
+  datasource:
+    url: jdbc:oracle:thin:@${ORACLE_DSN}
+    username: ${ORACLE_USER}
+    password: ${ORACLE_PASSWORD}
+    driver-class-name: oracle.jdbc.OracleDriver
+    hikari:
+      minimum-idle: 2
+      maximum-pool-size: 10
+      connection-timeout: 30000
+      idle-timeout: 600000
+      max-lifetime: 1800000
+      pool-name: TastebyHikariPool
+      connection-init-sql: "SELECT 1 FROM DUAL"
+
+  data:
+    redis:
+      host: ${REDIS_HOST:192.168.0.147}
+      port: ${REDIS_PORT:6379}
+      database: ${REDIS_DB:0}
+      timeout: 2000ms
+
+  jackson:
+    default-property-inclusion: non_null
+    serialization:
+      write-dates-as-timestamps: false
+
+app:
+  jwt:
+    secret: ${JWT_SECRET:tasteby-dev-secret-change-me}
+    expiration-days: 7
+
+  cors:
+    allowed-origins: http://localhost:3000,http://localhost:3001
+
+  oracle:
+    wallet-path: ${ORACLE_WALLET:}
+
+  oci:
+    compartment-id: ${OCI_COMPARTMENT_ID}
+    chat-endpoint: ${OCI_CHAT_ENDPOINT:https://inference.generativeai.us-ashburn-1.oci.oraclecloud.com}
+    embed-endpoint: ${OCI_GENAI_ENDPOINT:https://inference.generativeai.us-chicago-1.oci.oraclecloud.com}
+    chat-model-id: ${OCI_CHAT_MODEL_ID}
+    embed-model-id: ${OCI_EMBED_MODEL_ID:cohere.embed-v4.0}
+
+  google:
+    maps-api-key: ${GOOGLE_MAPS_API_KEY}
+    youtube-api-key: ${YOUTUBE_DATA_API_KEY}
+
+  cache:
+    ttl-seconds: 600
+
+logging:
+  level:
+    com.tasteby: DEBUG
+    org.springframework.jdbc: DEBUG