Modal retry ignores an exact collision already terminal in the retained stream

Summary

In release/v0.1.0, Modal exhausted-task recovery can have a complete exact selected-worktree lock-collision terminal sequence already at the tail of the retained workflow stream. The subsequent exact retry-task command then reports reset/start pre-ownership failure, appends no event, and does not preserve the collision cause in its command output. The worker checks only current command output or a suffix appended after the retry fingerprint, so it ignores the existing terminal proof and fails before ownership.

Generic reproduction

Use an in-memory NDJSON stream and /tmp/generic-linked-worktree/index.lock:

1. Append one complete same-run sequence: RunStarted, matched frame/snapshot pairs, and terminal RunFailed whose cause is exactly:

   Command failed: git read-tree --reset -u aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
   fatal: Unable to create '/tmp/generic-linked-worktree/index.lock': File exists.
   

2. Fingerprint that stream.

3. Simulate retry-task returning the exact RETRY_TASK_FAILED JSON plus exact reset-finished / starting-run pre-ownership logs, but no collision cause.

4. Append no event; the stream stays byte-identical. The selected lock is absent after the subprocess exits.

Observed predicates:

{
  "preceding_terminal_exact_collision": true,
  "command_preownership_shape": true,
  "current_command_exact_collision": false,
  "stream_unchanged": true,
  "delayed_suffix_present": false,
  "selected_lock_present_after_exit": false
}

The release worker rejects this state even though the retained stream and current command together prove the same narrow pre-ownership recovery boundary.

Expected behavior

Within the existing three-command cap, retry only when all of these hold:

• the stream already ends in a complete same-run terminal exact selected-lock collision with no NodeStarted;
• retry-task has the exact reset/start pre-ownership command shape;
• the stream remains byte-identical across retry-task;
• the selected lock is absent after the subprocess exits.

Unexpected stream events, unrelated terminal causes, current ownership, unsafe or remaining locks, and exhausted retry bounds must remain terminal.

Version

• Branch: release/v0.1.0
• Commit: 9b0bc8cab2e681bbffeee385c1f80f85a47087d3

Start in the release/v0.1.0 worker at commit 9b0bc8cab2e681bbffeee385c1f80f85a47087d3 and reproduce the in-memory NDJSON sequence with the selected index.lock collision. Trace retry-task handling around the retained terminal stream and verify the three-command cap. Done means the exact pre-ownership conditions permit retry while unrelated events, ownership, unsafe locks, and exhausted bounds remain terminal.