## Why
The `core` and `tui` Bazel targets treated nearly their entire crate trees as
compile-time data, mixing embedded runtime resources with source files and test
fixtures.
## What changed
- Move embedded resources for `core` and `tui` into dedicated `assets/`
directories and update their `include_str!` paths.
- Restrict Bazel compile data to explicit asset and frame directories.
- Move test-only prompts into `tests/fixtures`, resolve the core prompt through
`find_resource!`, and reuse the integration-test file glob when assembling
Bazel test data.
GitOrigin-RevId: eee9b0e41df77ea2604215a7f7333a6fe8317bfa
## Why
The Responses API test support already has structured SSE event
builders. Keeping separate JSON fixture loaders made small mock streams
harder to read and left an on-disk fixture for a single event.
## What changed
- Removed `load_sse_fixture` and `load_sse_fixture_with_id_from_str`
from `core_test_support`.
- Deleted the one `tests/fixtures/incomplete_sse.json` Responses API
fixture.
- Replaced the remaining call sites with `responses::sse(...)` and
existing event helpers.
## Validation
- `cargo test -p codex-core --test all
stream_no_completed::retries_on_early_close`
- `cargo test -p codex-core --test all
history_dedupes_streamed_and_final_messages_across_turns`
- `cargo test -p codex-core --test all review::`
Summary:
- replace the `sse_completed` fixture and related JSON template with
direct `responses::ev_completed` payload builders
- cascade the new SSE helpers through all affected core tests for
consistency and clarity
- remove legacy fixtures that were no longer needed once the helpers are
in place
Testing:
- Not run (not requested)
