fix(session): close turns left open by a process that died

[filipeforattini]

The complaint this answers

"fica aquele build infinito fazendo nada… tudo o que eu escrevo fica queued"

Two different failures were being treated as one. The live turn that stalls is covered by the
watchdog and the other guards in 0.14.0. This is the other one, and nothing addressed it.

time.completed on an assistant message is written by the process running the turn. When that
process is killed — an OOM (which this user hit repeatedly), a machine going to sleep, a crash —
nobody writes it. The message stays open forever.

The TUI computes its QUEUED badge purely from that:

pending = last assistant message with no time.completed
queued  = every message after it

So a session that survived one OOM stamps QUEUED on everything typed from then on, across
restarts, with no agent running. The server processes those messages perfectly well — nothing
gates on it — but the interface says the opposite, and there is no way for the user to tell it
apart from a real queue. There was no recovery of dangling messages anywhere: not on boot, not on
load, not on the next turn.

The fix, in two halves

• Server: a fresh run closes anything left open first. Only one run exists per session at a
  time, and a turn interrupted while its process lives finalizes itself on the way out — so an open
  message found at the start of a new run belongs to a run that is gone. It is marked aborted with
  "The process ended before this turn finished." and recorded through the guard log from feat(session): record every guard intervention #112, so a
  week of these says the OOM came back.
• TUI: the QUEUED badge now requires the session to actually be busy. An open message alone is
  not a queue.

Verification

• Integration test seen failing first (the abandoned message stayed open, no trip recorded) and
  passing after: the message is closed with MessageAbortedError, the turn still runs normally, and
  the trip is counted under orphan.
• Unit tests for the detection, including several crashes in a row and messages that are already
  finished.
• packages/redcode session suite 456 pass, packages/tui 228 pass.

https://claude.ai/code/session_014XwJPDhq1ahcm3rd454WzQ

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