fix(tests): repair TestUnifiedSearch and TestWebSocketProgressBroadcast

TestUnifiedSearch: Search for 'zzzznonexistent' instead of 'test' which
matches leftover test data from other tests. Fixes false 200 instead of 404.

TestWebSocketProgressBroadcast: Update to new progress endpoint
/api/media-items/:id/progress with correct PUT body format matching
ProgressService (percentage, epubcfi). Use book_id instead of
media_item_id to match WebSocket broadcast payload field names.

cmd/server/tests/websocket_test.go

@@ -119,19 +119,14 @@ func TestWebSocketProgressBroadcast(t *testing.T) {
 	ws.SetReadDeadline(time.Now().Add(5 * time.Second))
 	_, _, _ = ws.ReadMessage()
 
-	// Update progress via HTTP API
+	// Update progress via HTTP API to new media-item progress endpoint
 	progressReq := map[string]interface{}{
-		"source": "test",
-		"location": map[string]interface{}{
-			"percentage": 0.5,
-		},
-		"device_metadata": map[string]interface{}{
-			"device_type": "web",
-		},
+		"percentage": 0.5,
+		"epubcfi":    "epubcfi(/6/4/2:10)",
 	}
 	body, _ := json.Marshal(progressReq)
 
-	req, _ := http.NewRequest("POST", setup.Server.URL+"/api/progress/"+mediaID, strings.NewReader(string(body)))
+	req, _ := http.NewRequest("PUT", setup.Server.URL+"/api/media-items/"+mediaID+"/progress", bytes.NewBuffer(body))
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("Authorization", "Bearer "+token)