fix(ocr): log debug instead of silently swallowing person name resolution errors

Replaces catch(Exception ignored){} with log.debug() in getTrainingInfo().
Adds controller test documenting the graceful degradation behavior
(response stays 200 when personService.getById() throws).

Fixes reviewer concerns from @felixbrandt and @nullx.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/test/java/org/raddatz/familienarchiv/controller/OcrControllerTest.java

@@ -229,6 +229,23 @@ class OcrControllerTest {
                 .andExpect(jsonPath("$.ocrServiceAvailable").value(true));
     }
 
+    @Test
+    @WithMockUser(authorities = "ADMIN")
+    void getTrainingInfo_returns200_and_omits_personName_when_resolution_throws() throws Exception {
+        UUID personId = UUID.randomUUID();
+        OcrTrainingRun runWithPerson = OcrTrainingRun.builder()
+                .id(UUID.randomUUID()).status(TrainingStatus.DONE)
+                .personId(personId).blockCount(5).documentCount(1).modelName("sender_x").build();
+        OcrTrainingService.TrainingInfoResponse info =
+                new OcrTrainingService.TrainingInfoResponse(5, 20, 2, 3, true, null, List.of(runWithPerson));
+        when(ocrTrainingService.getTrainingInfo()).thenReturn(info);
+        when(personService.getById(personId)).thenThrow(new RuntimeException("DB error"));
+
+        mockMvc.perform(get("/api/ocr/training-info"))
+                .andExpect(status().isOk())
+                .andExpect(jsonPath("$.personNames").isEmpty());
+    }
+
     @Test
     @WithMockUser(authorities = "READ_ALL")
     void getDocumentOcrStatus_returnsNone_whenNoOcrJobExists() throws Exception {