Repair TUI thread routing stack

[andrei-hasna]

Summary

• consolidate the stale TUI stack from Add interactive /changelog promptbar browser #93, Add interactive workflows TUI manager #139, fix(tui): stop leaking unrelated thread events into pre-primary startup buffer #176, Filter agent picker entries by verified spawn lineage #177, fix(tui): harden usage heartbeat and auth-profile auto-switch #180, and Guard agent picker from scheduled thread leaks #199 into one current branch
• treat fix(tui): isolate scheduled top-level threads from the agent picker #185 as superseded while keeping its /agent picker refresh guard
• route pre-primary thread events/requests by addressed thread, filter agent picker rows by verified spawn lineage, and harden auth-profile usage heartbeat/auto-switch behavior
• add promptbar changelog browser and workflow manager UI with focused snapshots/tests

Verification

• cargo fmt --manifest-path codex-rs/Cargo.toml --all
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-core usage_profile_health
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib scheduled_top_level_thread
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib workflow_manager
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib slash_changelog
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib auto_switch_skips_recently_failed_profile_for_unknown_candidate
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib open_agent_picker
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib enqueue_primary_thread_session
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib finds_loaded_subagent_tree_for_primary_thread
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib changelog_browser
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib thread_started
• cargo test --manifest-path codex-rs/Cargo.toml -p codex-tui --lib pre_primary_untracked_request_stays_resolvable_on_addressed_thread
• git diff --check
• todos redaction scan --file /tmp/pr0-wave2-tui-routing-commit.diff

Notes

• Full codex-tui --lib was attempted, but the broad suite aborted on an unrelated existing stack overflow in app::tests::loop_actions_ignore_explicit_schedule_ids. The targeted stack tests above passed.
• Independent adversarial review on account004 found two issues before PR creation: pre-primary untracked ServerRequest orphaning and workflow manager loading-view stacking/spec-id redaction. Both were fixed and covered by targeted regression tests.
• Local commit/push hooks reported lefthook missing from PATH; explicit diff hygiene and redaction scans passed before push.

[andrei-hasna]

Replacement-wave queue state: deferred to the app-server/TUI lane, not a merge candidate in this lane.

Reason: #211 is a large TUI/thread-routing/workflow-manager stack (34 files, +2967/-326) and is currently conflict-marked against current main (DIRTY / CONFLICTING, rebaseable=false by live triage). It is not fully superseded, but it overlaps heavily with app-server/TUI workflow PRs including #143 and #219.

Required next lane action:

• app-server/TUI lane should salvage/split only the still-desired unique pieces after feat(workflows): add thread workflow delete RPC and enable TUI Delete action #143/Handle usage-limit reset credits #219 ownership is resolved;
• likely candidates to inspect: thread routing fixes, auth-profile usage heartbeat/auto-switch behavior, changelog browser, workflow-manager UI/tests/snapshots, and usage_profile_health;
• all compile/test/snapshot work must run in E2B only.

No local build/test/schema output is accepted as evidence for this PR.