Forward thread originators from standalone extensions (#33677)

## Why

Standalone web search and image requests need to preserve the trusted,
thread-scoped originator used for billing attribution.

## What changed

- Seed extension data with the resolved thread originator and recognize
  `codex_work_cca` and `chatgpt_cca` service names as originators.
- Forward non-default originators from the web search and image generation
  extensions with the shared originator-header helper.

## Testing

- Cover originator resolution, header validation, and forwarding for web
  search, image generation, and image editing.

GitOrigin-RevId: 165dace8e4d24e4bd92f234bff5ec77a21a7ff6e

codex-rs/core/src/thread_manager_tests.rs

@@ -135,6 +135,24 @@ fn effective_originator_prefers_thread_scoped_sources_before_env_originator() {
             Some("inherited_originator"),
             "codex_work_mobile",
         ),
+        (
+            Some("codex_work_cca"),
+            Some("persisted_originator"),
+            Some("inherited_originator"),
+            "codex_work_cca",
+        ),
+        (
+            Some("chatgpt_cca"),
+            Some("persisted_originator"),
+            Some("inherited_originator"),
+            "chatgpt_cca",
+        ),
+        (
+            Some("chatgpt_cca_extra"),
+            Some("persisted_originator"),
+            Some("inherited_originator"),
+            "persisted_originator",
+        ),
         (
             None,
             Some("persisted_originator"),