Support image references by file ID in inputs and tool outputs (#45794)

## What changed

- Accept `fileId` alongside the existing `url` form for app-server image inputs, and forward file references to the Responses API as `file_id`. Update generated schemas and client types.
- Preserve file references, image detail hints, and mixed inline/file image ordering through user-message events, thread history, and rollout migration. Retain file images when truncating tool output.
- Pass file references through image preparation without resolving them, while keeping resize-notice numbering correct. Omit them from unsupported TUI display and Guardian image context.
- Reject image-edit requests whose recent-image window includes a file reference, preventing selection of an older inline image instead.

## Testing

Add coverage for serialization, request and rollout preservation, mixed-image history ordering, incomplete ordering metadata, tool-output truncation, and rejection of unsupported image-edit selections.

GitOrigin-RevId: 6ca20a8577155cc934b720803c3b7b3bffdf972a

codex-rs/app-server-protocol/schema/json/ServerNotification.json

@@ -1771,6 +1771,18 @@
               ],
               "title": "ImageUrlFunctionCallOutputContentItem",
               "type": "object"
+            },
+            {
+              "properties": {
+                "file_id": {
+                  "type": "string"
+                }
+              },
+              "required": [
+                "file_id"
+              ],
+              "title": "FileIdFunctionCallOutputContentItem",
+              "type": "object"
             }
           ],
           "properties": {
@@ -6469,6 +6481,32 @@
           "type": "object"
         },
         {
+          "anyOf": [
+            {
+              "properties": {
+                "url": {
+                  "type": "string"
+                }
+              },
+              "required": [
+                "url"
+              ],
+              "title": "UrlUserInput",
+              "type": "object"
+            },
+            {
+              "properties": {
+                "fileId": {
+                  "type": "string"
+                }
+              },
+              "required": [
+                "fileId"
+              ],
+              "title": "FileIdUserInput",
+              "type": "object"
+            }
+          ],
           "properties": {
             "detail": {
               "anyOf": [
@@ -6487,14 +6525,10 @@
               ],
               "title": "ImageUserInputType",
               "type": "string"
-            },
-            "url": {
-              "type": "string"
             }
           },
           "required": [
-            "type",
-            "url"
+            "type"
           ],
           "title": "ImageUserInput",
           "type": "object"