Remove sync-branches workflow — made redundant by per-iteration Step 3 ahead/behind logic

[mrjf]

Summary

Remove workflows/sync-branches.md (and its lock file on consumers) from autoloop. The workflow was designed when the per-iteration branch-management logic was minimal; now that each iteration runs a full ahead/behind fast-forward-or-merge at Step 3 (#36), sync-branches is scaffolding without a load-bearing purpose.

Leaving it in is actively harmful: it can't compile under strict mode (see #33), it requires a PAT to actually push (most consumer repos don't configure one), and when it silently fails pushes the workflow still looks green — so users see "sync-branches: success" on their runs while nothing is actually syncing.

Why it's redundant

Before #36, Step 3 of the iteration loop was a simple "merge main if it exists, else create from main." If main advanced between iterations, the branch drifted, and sync-branches was the between-iterations correction.

After #36, Step 3 does:

ahead=$(git rev-list --count origin/main..origin/autoloop/{program-name})
behind=$(git rev-list --count origin/autoloop/{program-name}..origin/main)

if [ "$ahead" = "0" ] && [ "$behind" != "0" ]; then
  # Lossless fast-forward
  git checkout -B autoloop/{program-name} origin/main
  git push --force-with-lease origin autoloop/{program-name}
elif [ "$ahead" != "0" ] && [ "$behind" != "0" ]; then
  # True divergence
  git merge origin/main --no-edit
else
  # Up to date
fi

Each iteration now self-heals the branch. sync-branches's original job is covered.

What sync-branches still technically does, and why we don't need it

Residual role	Why it doesn't justify a whole workflow
Bring a paused program's branch up to date with main	Program is paused by design — no iteration runs, no stale-branch problem to solve. Unfreezing happens when maintainers act.
Catch merge conflicts with main before the next iteration runs	Step 3 catches them the same way, at the moment they're about to matter, with the agent on hand to resolve.
Reduce "N commits behind main" banner on open PRs between iterations	Cosmetic.
Propagate fixes on main to active branches faster than the iteration schedule	Marginal. The next scheduled run does it within the schedule window (30 min for frequent programs, 6 h for slow ones).

Concrete removal

In this repo:

1. git rm workflows/sync-branches.md
2. Remove the gh aw compile sync-branches line from install.md (Step 4).
3. Update README.md if sync-branches is mentioned.
4. Search docs for mentions of "sync-branches" or "sync workflow" and remove/update.
5. If there's a section in workflows/autoloop.md that cross-references sync-branches ("a sync workflow automatically merges the default branch into all active autoloop/* branches") — rewrite it to say that the per-iteration Step 3 handles branch freshness, and point to that section.

Migration for existing installs

Consumers who installed sync-branches previously need to remove it on upgrade:

1. Delete .github/workflows/sync-branches.md and .github/workflows/sync-branches.lock.yml in the consuming repo.
2. That's it. No state to clean up; no references to update.

This belongs in the release notes for whichever version lands this change. The versioning proposal in #46 would make the release-notes path natural.

Resolution of existing issues

• Step 4: gh aw compile sync-branches fails #33 (strict-mode compile error on sync-branches) — closed by removal. No more sync-branches, no more compile error.
• Any future issue asking "why does sync-branches silently no-op" — same resolution.

Acceptance

• workflows/sync-branches.md no longer exists in this repo.
• install.md no longer asks consumers to compile it.
• No doc references to sync-branches remain.
• Release notes (or the PR description, if versioning isn't ready) instruct existing installs how to remove their local copies.
• Step 4: gh aw compile sync-branches fails #33 is closed.

Related

• Step 4: gh aw compile sync-branches fails #33 — the compile-time failure that this removal resolves.
• Fast-forward the long-running branch to main when ahead=0, instead of always merging #36 — the per-iteration ahead/behind logic that makes sync-branches redundant.
• Basic versioning: VERSION file + self-check that opens an update-available issue on drift #46 — versioning proposal; release notes path for migration.