Add booking SSE stream and emit on updates

src/main/kotlin/com/android/trisolarisserver/component/BookingEvents.kt

@@ -0,0 +1,35 @@
+package com.android.trisolarisserver.component
+
+import com.android.trisolarisserver.controller.BookingSnapshotBuilder
+import com.android.trisolarisserver.controller.dto.BookingDetailResponse
+import org.springframework.scheduling.annotation.Scheduled
+import org.springframework.stereotype.Component
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter
+import java.util.UUID
+
+@Component
+class BookingEvents(
+    private val bookingSnapshotBuilder: BookingSnapshotBuilder
+) {
+    private val hub = SseHub<BookingKey>("booking") { key ->
+        bookingSnapshotBuilder.build(key.propertyId, key.bookingId)
+    }
+
+    fun subscribe(propertyId: UUID, bookingId: UUID): SseEmitter {
+        return hub.subscribe(BookingKey(propertyId, bookingId))
+    }
+
+    fun emit(propertyId: UUID, bookingId: UUID) {
+        hub.emit(BookingKey(propertyId, bookingId))
+    }
+
+    @Scheduled(fixedDelayString = "25000")
+    fun heartbeat() {
+        hub.heartbeat()
+    }
+}
+
+private data class BookingKey(
+    val propertyId: UUID,
+    val bookingId: UUID
+)

src/main/kotlin/com/android/trisolarisserver/component/DocumentExtractionService.kt

@@ -19,7 +19,8 @@ class DocumentExtractionService(
     private val propertyRepo: PropertyRepo,
     private val paddleOcrClient: PaddleOcrClient,
     private val bookingRepo: BookingRepo,
-    private val pincodeResolver: PincodeResolver
+    private val pincodeResolver: PincodeResolver,
+    private val bookingEvents: BookingEvents
 ) {
     private val logger = LoggerFactory.getLogger(DocumentExtractionService::class.java)
 
@@ -476,6 +477,9 @@ class DocumentExtractionService(
         if (updated) {
             booking.updatedAt = OffsetDateTime.now()
             bookingRepo.save(booking)
+            val propertyId = booking.property.id ?: return
+            val bookingId = booking.id ?: return
+            bookingEvents.emit(propertyId, bookingId)
         }
     }
 }