PDF Text editor (#4724)

## Summary
- add a `PdfJsonConversionService` that serializes PDF text, fonts, and
metadata to JSON and rebuilds a PDF from the same structure
- expose REST endpoints for `/pdf/json` and `/json/pdf` conversions
using the existing convert API infrastructure
- define JSON model classes capturing document metadata, font
information, and positioned text elements

## Testing
- `./gradlew spotlessApply` *(fails: plugin
org.springframework.boot:3.5.4 unavailable in build environment)*
- `./gradlew build` *(fails: plugin org.springframework.boot:3.5.4
unavailable in build environment)*

------
https://chatgpt.com/codex/tasks/task_b_68f8e98d94ac8328a0e499e541528b6f

---------

Co-authored-by: EthanHealy01 <[email protected]>

app/common/src/test/java/stirling/software/common/service/JobExecutorServiceTest.java

@@ -78,6 +78,23 @@ class JobExecutorServiceTest {
         verify(request).setAttribute(eq("jobId"), anyString());
     }
 
+    @Test
+    void shouldExposeJobIdInJobContextDuringSyncExecution() throws Exception {
+        // Given
+        Supplier<Object> work = stirling.software.common.util.JobContext::getJobId;
+
+        // When
+        ResponseEntity<?> response = jobExecutorService.runJobGeneric(false, work);
+
+        // Then
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertNotNull(response.getBody());
+
+        var requestJobIdCaptor = ArgumentCaptor.forClass(String.class);
+        verify(request).setAttribute(eq("jobId"), requestJobIdCaptor.capture());
+        assertEquals(requestJobIdCaptor.getValue(), response.getBody());
+    }
+
     @Test
     void shouldRunAsyncJobSuccessfully() throws Exception {
         // Given