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>

ecosystem.config.js

@@ -2,22 +2,25 @@ module.exports = {
   apps: [
     {
       name: "tasteby-api",
-      cwd: "/Users/joungmin/workspaces/tasteby/backend",
-      script: "run_api.py",
-      interpreter: "/Users/joungmin/workspaces/tasteby/backend/.venv/bin/python",
-      env: {
-        PYTHONPATH: ".",
-      },
-    },
-    {
-      name: "tasteby-daemon",
-      cwd: "/Users/joungmin/workspaces/tasteby/backend",
-      script: "run_daemon.py",
-      interpreter: "/Users/joungmin/workspaces/tasteby/backend/.venv/bin/python",
-      env: {
-        PYTHONPATH: ".",
-      },
+      cwd: "/Users/joungmin/workspaces/tasteby/backend-java",
+      script: "./start.sh",
+      interpreter: "/bin/bash",
     },
+    // Python backend (disabled - kept for rollback)
+    // {
+    //   name: "tasteby-api-python",
+    //   cwd: "/Users/joungmin/workspaces/tasteby/backend",
+    //   script: "run_api.py",
+    //   interpreter: "/Users/joungmin/workspaces/tasteby/backend/.venv/bin/python",
+    //   env: { PYTHONPATH: "." },
+    // },
+    // {
+    //   name: "tasteby-daemon-python",
+    //   cwd: "/Users/joungmin/workspaces/tasteby/backend",
+    //   script: "run_daemon.py",
+    //   interpreter: "/Users/joungmin/workspaces/tasteby/backend/.venv/bin/python",
+    //   env: { PYTHONPATH: "." },
+    // },
     {
       name: "tasteby-web",
       cwd: "/Users/joungmin/workspaces/tasteby/frontend",