Pass turn id with feedback uploads (#17314)

## Summary
- Add an optional `tags` dictionary to feedback upload params.
- Capture the active app-server turn id in the TUI and submit it as
`tags.turn_id` with `/feedback` uploads.
- Merge client-provided feedback tags into Sentry feedback tags while
preserving reserved system fields like `thread_id`, `classification`,
`cli_version`, `session_source`, and `reason`.

## Behavior / impact
Existing feedback upload callers remain compatible because `tags` is
optional and nullable. The wire shape is still a normal JSON object /
TypeScript dictionary, so adding future feedback metadata will not
require a new top-level protocol field each time. This change only adds
feedback metadata for Codex CLI/TUI uploads; it does not affect existing
pipelines, DAGs, exports, or downstream consumers unless they choose to
read the new `turn_id` feedback tag.

## Tests
- `cargo fmt -- --config imports_granularity=Item` passed; stable
rustfmt warned that `imports_granularity` is nightly-only.
- `cargo run -p codex-app-server-protocol --bin write_schema_fixtures`
- `cargo test -p codex-feedback
upload_tags_include_client_tags_and_preserve_reserved_fields`
- `cargo test -p codex-app-server-protocol
schema_fixtures_match_generated`
- `cargo test -p codex-tui build_feedback_upload_params`
- `cargo test -p codex-tui
live_app_server_turn_started_sets_feedback_turn_id`
- `cargo check -p codex-app-server --tests`
- `git diff --check`

---------

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server-protocol/schema/json/v2/FeedbackUploadParams.json

@@ -22,6 +22,15 @@
         "null"
       ]
     },
+    "tags": {
+      "additionalProperties": {
+        "type": "string"
+      },
+      "type": [
+        "object",
+        "null"
+      ]
+    },
     "threadId": {
       "type": [
         "string",