feat: add browser push notifications

src/main/java/com/openisle/controller/PushSubscriptionController.java

@@ -0,0 +1,41 @@
+package com.openisle.controller;
+
+import com.openisle.service.PushSubscriptionService;
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/push")
+@RequiredArgsConstructor
+public class PushSubscriptionController {
+    private final PushSubscriptionService pushSubscriptionService;
+    @Value("${app.webpush.public-key}")
+    private String publicKey;
+
+    @GetMapping("/public-key")
+    public PublicKeyResponse getPublicKey() {
+        PublicKeyResponse r = new PublicKeyResponse();
+        r.setKey(publicKey);
+        return r;
+    }
+
+    @PostMapping("/subscribe")
+    public void subscribe(@RequestBody SubscriptionRequest req, Authentication auth) {
+        pushSubscriptionService.saveSubscription(auth.getName(), req.getEndpoint(), req.getP256dh(), req.getAuth());
+    }
+
+    @Data
+    private static class PublicKeyResponse {
+        private String key;
+    }
+
+    @Data
+    private static class SubscriptionRequest {
+        private String endpoint;
+        private String p256dh;
+        private String auth;
+    }
+}