[Tobias-Fischer]

#179 added packing by measured times, but kept the old count batching next to it, and neither respected GitHub's 500 KiB workflow limit by itself. On Windows, where each job carried about 5.7 KiB of inlined scripts, a workflow packed by time came out at up to 1.8 MiB. RoboStack had to retry with fewer runners and larger batches, and finally fall back to count batching.

One batching logic, with or without times (batch_stages):

1. Fewest jobs first: every stage gets as few jobs as --batch_size (packages per job) allows. Consecutive short stages, of at most 2 minutes each, share a job up to --batch_size packages. They run one after another anyway, so sharing costs no time.
2. Spend the budget where it helps most: while the job budget lasts, the stage whose duration more jobs cut the most, per added job, gets them. Its packages are packed longest first, with at most one job per runner. The search looks past plateaus: 8 equal packages get faster again only at 8 jobs once they have 4.
3. Without --timings, every package counts the same (BuildTimings' default), which splits the largest stages first. Count mode as such is gone.

The budget comes from the size limit: when the generated workflow is too large (WorkflowTooLarge), vinca-gha batches again with a budget scaled down by how much it is over. The slowest stages stay split, and callers no longer need their own retries.

Smaller jobs, so more of them fit:

• The Windows jobs call .scripts\build_win.bat from their checkout instead of carrying its text, which was 2–3 KiB per job. That's the same file vinca inlined, which vinca-gha still requires.
• The Build steps no longer repeat the job's package list in their name.

Simulated on RoboStack's jazzy full rebuild (the generated workflows, with the measured per-recipe times):

	jobs	workflow size	wall time (20 runners / 8 runners)
linux-64, today (count)	117	292 KiB	6.41 h
linux-64, #179 timed	219	374 KiB	2.65 h / 3.04 h
linux-64, this PR, timed	214	302 KiB	2.60 h / 3.00 h
linux-64, this PR, no times	363	470 KiB	2.96 h / 3.16 h
win-64, today (count)	90	514 KiB (over the limit)	25.0 h
win-64, #179 timed	401	1859 KiB (over the limit)	6.0 h
win-64, this PR, timed	181	493 KiB	8.87 h / 9.14 h
win-64, this PR, no times	178	486 KiB	11.6 h

The size loop needed at most one retry.

The remaining Windows overhead is the inlined conda-forge build setup script, about 1.3 KiB per job. Moving it into the repository as well would fit about twice as many Windows jobs again, which could be a follow-up.

Tests:

• updated for the merged short stages and longest-first packing;
• new tests for the budget going to the slowest stages, splitting without times, and the Windows build script being called;
• all 308 pass, and ruff is clean.

🤖 Claude (AI assistant), on behalf of @Tobias-Fischer

🤖 Generated with Claude Code