feat: add GET /history/recent endpoint for cross-list activity

src/main/java/de/zendric/app/xpensely_server/controller/ExpenseListController.java

@@ -15,6 +15,7 @@ import org.springframework.web.server.ResponseStatusException;
 
 import de.zendric.app.xpensely_server.model.*;
 import de.zendric.app.xpensely_server.model.DTO.HistoryPageDto;
+import de.zendric.app.xpensely_server.model.DTO.RecentHistoryEntryDto;
 import de.zendric.app.xpensely_server.security.AuthenticatedUserResolver;
 import de.zendric.app.xpensely_server.services.CategoryService;
 import de.zendric.app.xpensely_server.services.ExpenseListService;
@@ -194,6 +195,14 @@ public class ExpenseListController {
         return ResponseEntity.ok(historyService.getHistory(id, page, size));
     }
 
+    @GetMapping("/history/recent")
+    public ResponseEntity<List<RecentHistoryEntryDto>> getRecentHistory(
+            @RequestParam(defaultValue = "4") int limit,
+            Authentication authentication) {
+        AppUser user = authenticatedUserResolver.resolveCurrentUser(authentication);
+        return ResponseEntity.ok(historyService.getRecentForUser(user, limit));
+    }
+
     private void assertOwner(AppUser authenticated, ExpenseList list) {
         if (!list.getOwner().getId().equals(authenticated.getId()))
             throw new ResponseStatusException(HttpStatus.FORBIDDEN);

src/test/java/de/zendric/app/xpensely_Server/controller/ExpenseListControllerTest.java

@@ -3,6 +3,7 @@ package de.zendric.app.xpensely_Server.controller;
 import de.zendric.app.xpensely_server.controller.ExpenseListController;
 import de.zendric.app.xpensely_server.model.AppUser;
 import de.zendric.app.xpensely_server.model.DTO.HistoryPageDto;
+import de.zendric.app.xpensely_server.model.DTO.RecentHistoryEntryDto;
 import de.zendric.app.xpensely_server.model.Expense;
 import de.zendric.app.xpensely_server.model.ExpenseList;
 import de.zendric.app.xpensely_server.security.AuthenticatedUserResolver;
@@ -370,4 +371,49 @@ class ExpenseListControllerTest {
         mockMvc.perform(get("/api/expenselist/99/history"))
                 .andExpect(status().isNotFound());
     }
+
+    // --- Recent history endpoint ---
+
+    @Test
+    void getRecentHistory_returnsArrayWithListInfo() throws Exception {
+        AppUser user = new AppUser(); user.setId(1L); user.setUsername("alice");
+        when(authenticatedUserResolver.resolveCurrentUser(any())).thenReturn(user);
+        when(historyService.getRecentForUser(user, 4)).thenReturn(List.of(
+                new RecentHistoryEntryDto("UPDATED", "alice", "Groceries",
+                        LocalDateTime.of(2026, 7, 6, 12, 0), 10L, "Trip to Rome")));
+
+        mockMvc.perform(get("/api/expenselist/history/recent"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$[0].type").value("UPDATED"))
+                .andExpect(jsonPath("$[0].actorUsername").value("alice"))
+                .andExpect(jsonPath("$[0].expenseTitle").value("Groceries"))
+                .andExpect(jsonPath("$[0].listId").value(10))
+                .andExpect(jsonPath("$[0].listName").value("Trip to Rome"));
+    }
+
+    @Test
+    void getRecentHistory_passesLimitParam() throws Exception {
+        AppUser user = new AppUser(); user.setId(1L);
+        when(authenticatedUserResolver.resolveCurrentUser(any())).thenReturn(user);
+        when(historyService.getRecentForUser(user, 10)).thenReturn(List.of());
+
+        mockMvc.perform(get("/api/expenselist/history/recent").param("limit", "10"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$").isEmpty());
+    }
+
+    @Test
+    void getRecentHistory_doesNotClashWithPerListHistoryRoute() throws Exception {
+        // /api/expenselist/1/history must still hit the per-list handler.
+        AppUser owner = new AppUser(); owner.setId(1L); owner.setUsername("alice");
+        ExpenseList list = new ExpenseList(); list.setId(1L); list.setOwner(owner);
+        when(expenseListService.findById(1L)).thenReturn(Optional.of(list));
+        when(authenticatedUserResolver.resolveCurrentUser(any())).thenReturn(owner);
+        when(historyService.getHistory(1L, 0, 30))
+                .thenReturn(new HistoryPageDto(List.of(), false));
+
+        mockMvc.perform(get("/api/expenselist/1/history"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.entries").isArray());
+    }
 }