## Why
`chatwidget.rs` is still carrying too many unrelated responsibilities in
one file. #22269 started a five-phase cleanup to move coherent behavior
domains into focused modules while keeping `chatwidget.rs` as the
composition layer. #22407 completed phase 2 by extracting input and
submission flow, #22433 completed phase 3 by extracting protocol,
replay, streaming, and tool lifecycle handling, and #22518 completed
phase 4 by extracting settings, popups, and status surfaces.
This PR is phase 5. It cleans up the remaining constructor and
orchestration code now that the larger behavior domains have moved out,
leaving `chatwidget.rs` much closer to the composition layer the cleanup
was aiming for. This is once again a mechanical movement of existing
functions. No functional changes.
## What Changed
- Added focused modules for widget construction and initial wiring,
session configuration flow, key/composer interaction routing, review
popup orchestration, desktop notification coalescing, and render
composition.
- Moved the remaining constructor, session setup, interaction,
notification, review picker, and rendering helpers out of
`codex-rs/tui/src/chatwidget.rs`.
- Preserved the existing startup/session behavior, keyboard handling,
review picker flow, notification priority behavior, and render
composition while shrinking the central widget module substantially.
- Left `codex-rs/tui/src/chatwidget.rs` as the registration and
composition surface for the extracted behavior modules.
## Cleanup Phases
The five-phase cleanup plan from #22269 is:
1. Phase 1: mechanical helper and state moves. Completed in #22269.
2. Phase 2: extract input and submission flow, including queued user
messages, shell prompt submission, pending steer restoration, and thread
input snapshot/restore behavior. Completed in #22407.
3. Phase 3: extract protocol, replay, streaming, and tool lifecycle
handling, while preserving active-cell grouping, transcript
invalidation, interrupt deferral, and final-message separator behavior.
Completed in #22433.
4. Phase 4: extract settings, popups, and status surfaces, including
model/reasoning/collaboration/personality popups, permission prompts,
rate-limit UI, and connectors helpers. Completed in #22518.
5. Phase 5: clean up the remaining constructor and orchestration code
once the larger behavior domains have moved out, leaving `chatwidget.rs`
as the composition layer. This PR.
## Verification
- `cargo check -p codex-tui`
- `cargo test -p codex-tui chatwidget::tests::popups_and_settings`
- `cargo test -p codex-tui chatwidget::tests::plan_mode`
- `cargo test -p codex-tui chatwidget::tests::review_mode`
- `cargo test -p codex-tui chatwidget::tests::status_and_layout`
`cargo test -p codex-tui` also compiles and begins running, but aborts
in the unchanged app-side test
`app::tests::discard_side_thread_keeps_local_state_when_server_close_fails`
with the same reproducible stack overflow noted in phase 4.
Eric Traut