[snimu]

After the session re-attach window expired, a later successful reconnect still left every submit blocked with "Daemon reconnection failed". This PR clears that failure on every successful attach.

Bug

When the direct worker link dies, the session-plane driver retries the attach for a fixed 1-minute window. When the window expires, it sets SessionUi.reconnection_failed, and send_prompt refuses every submit while that is set. Only a later session-plane success cleared it.

These paths attach a healthy connection but never cleared the flag:

• a full reconnect (lost link, shutdown, or update recovery)
• /switch and /new
• a session_binding rebind

So after any of them, every submit was still refused.

Fix

attach_session now clears reconnection_failed next to daemon_closing_notice. Both are per-connection state. Every successful attach goes through attach_session, including the session-plane driver and the recovery reattach. Because of that, the separate clear in the session-plane success arm (run.rs) is deleted. One comment in reconnect.rs named this bug as a reason for the shutdown yield rule; that clause is removed.

Test

New unit test an_attach_clears_the_reconnection_failure in session_ui/lifecycle.rs. It sits on the layer that owns the flag and reuses the module's existing mock_session helper. The test sets reconnection_failed, calls attach_session against the mock daemon, and asserts the flag is None.

Mutation check (Prime sandbox): with the new self.reconnection_failed = None; line removed from attach_session, the test fails:

panicked at crates/pa-tui/src/session_ui/lifecycle.rs:977:13:
  left: Some("the session worker is gone")
 right: None

An earlier revision of this PR had a minute-long headless e2e. It drove the full path: direct link lost, the window expires, full reconnect, then a submit. On main, that e2e showed the submit refused after the reconnect:

 Daemon restarted (v0.10.2) - reconnected
 ⚠ Error: Daemon reconnection failed: the daemon rejected the attach request: the session worker is gone
 >  hello

It was replaced by the unit test above to keep the suite fast.

Validation

All green in a Prime sandbox with toolchain 1.98.1:

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test -p pa-tui --no-fail-fast
• cargo build -p pa-cli

Overlap

#3893, #3424 and #3650 touch run.rs, session_ui.rs and lifecycle.rs; #3825 touches run.rs. The production change here is one added line in attach_session and one deleted line in run.rs, so conflicts should be trivial.

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Note

Low Risk
Small lifecycle/state-reset change on the attach path; no new networking or auth behavior, with a targeted unit test.

Overview
Fixes prompts staying blocked with "Daemon reconnection failed" after the TUI had already reattached to a healthy daemon.

Previously reconnection_failed was only cleared on one session-plane reconnect success path in run.rs, even though other recoveries (attach_session, shutdown/lost reconnect, /switch, rebind) also established a live connection. attach_session now clears reconnection_failed with daemon_closing_notice on every successful attach, and the redundant clear in the reconnect success arm is removed.

Docs/comments in session_ui and reconnect.rs reflect that this flag is per-connection. A focused unit test asserts an attach wipes a preset failure state.

^{Reviewed by Cursor Bugbot for commit 5fb51fc. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Clear SessionUi.reconnection_failed in attach_session instead of reconnect handling

The TUI could keep showing "Daemon reconnection failed" and block submits even after a later reconnect succeeded, because the failure marker was only cleared in one branch of the reconnect flow.

• Moves the clearing of reconnection_failed to SessionUi.attach_session in lifecycle.rs, so every successful attach clears it after reconstructed session state is applied.
• Removes the old clearing from the successful-reconnect branch in run.rs after transcript resynchronization.
• Adds a regression test (an_attach_clears_the_reconnection_failure) and a release note in .changes/tui-reconnect-failed-sticky.md.

^{Macroscope summarized 5fb51fc.}