[hakuturu583]

🐛 Bug Fix

Fixes #1566.

examples/run.py wrote batch_results.json only after run_all() returned, and never after Ctrl-C or SIGTERM. The viewer decides whether a directory is a batch only from that file. So while a glob batch ran, or for ever after an interrupt, the viewer listed it as a single run of its first case: a batch with 2 failures out of 3 showed as "1/1 passed". batch_report.py also wrote the file with a plain write_text, so a reader could see it half-written.

🛠️ Changes

• atomic_file.py (new, Codon-CHECKED): write_text_atomically(path, text) writes a temp file in the same directory, sets 0o644 and os.replaces it over the target, removing the temp file on any exception. It is factored out of maps.cache._write_atomically, which now calls it.
• batch_report.py: write_batch_result_json writes atomically. The content and schema are unchanged.
• scenario_queue.py: run_all(on_result=...), called once per case after its last attempt, including errored cases. The call sits outside the retry try, so it is never counted as a failed attempt.
• examples/run.py (run_batch): rewrites batch_results.json after each case, and once more in a finally if interrupted, with the cases run so far and in the same schema. A failed progress write is logged, and the batch keeps going. A completed batch gets the same file as before.
• Tests:
  • test_batch_results_progress.py:
    • a batch interrupted after 2 of 3 cases lists as a batch, 1/2, with no temp file;
    • an interruption before any case writes nothing;
    • an interruption before the rename keeps the old file;
    • the atomic write replaces the file whole.
  • test_scenario_queue.py: on_result is called once per case, including retried and errored cases.

⚠️ Breaking Changes

None. batch_results.json is now always mode 0o644, where it used to follow the umask.

🔍 Review

A fresh-context review passed it. It confirmed:

• progress files and the final file have the same shape;
• no viewer reader depends on rerun_errors, which is absent from progress files as it is from a final file with no errors;
• totals come from the entries, so missing cases are never shown as passed;
• the temp name never matches the scanner's globs;
• SLURM runs are unaffected.

Optional points it noted that this PR doesn't take:

• an errored case can be missing from an interrupted file if the following reset_world() raises;
• one test raises KeyboardInterrupt where a RuntimeError would prove more.

✅ Testing

• Codon: scenario-check --library on atomic_file, batch_report, maps.cache and scenario_queue passed (4 checked modules and the 154 they import).
• Targeted tests: 1452 passed, 2 skipped. Library and sweep tests: 67 passed.
• pre-commit run --files on the changed files: all hooks pass.

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