Move the rebase and resolve-rebase-conflicts scripts into agentrepo rebase #326

Outcome

Run rebase preflight, saved replay state, start and continue,
stopped-status reporting, verification, conflict classification,
token proposals, proven sorted unions and explicit side choice
through agentrepo rebase. The existing Go marker recognition is
reused, and #321 supplies the single launcher.

The non-owner shell and the coupled Python stay frozen, with no new
shell logic, through the N-2 compatibility window. The last three
children then remove their algorithms while preserving the required
fixed forwarding paths.

Part of #588.

Done when

• All fifteen children are merged.
• Every Bats and Python case has equivalent executing Go coverage
  or a named retained shell-specific reason.
• Generated output, tokens and lock records agree.
• Statuses, streams, filesystem effects and refusals have parity
  evidence.
• The native Go cases execute on macOS, Linux and Windows.
• The command release and the two-release warning history
  precede the fallback deletion.
• The leak scans come back clean for this epic's own text and
  posts.
• A closing comment checks every item above against evidence.

Children

Build order follows this list. The two-digit identifiers are stable
references used in the child bodies. Children 01 to 09 add Go
behavior without switching callers; child 10 activates the generated
workflows through #321's shared launcher; children 11 and 12 retire
tests that have equivalent Go coverage; children 13 to 15 remove
non-owner fallbacks after N-2.

• Read rebase preflight and recovery state in Go #895
• Start and continue a rebase with the existing safeguards in Go #896
• Report a stopped rebase from Go #897
• Verify the replayed branch from Go #898
• Prove append-only sorted unions in Go #899
• Preserve token-union proposals in Go #900
• Classify stopped conflicts and print their evidence in Go #901
• Write and independently verify sorted-union resolutions in Go #902
• Resolve one path by an explicit side in Go #903
• Activate both skill workflows through the shared launcher #904
• Retire rebase Bats cases covered by Go tests #905
• Retire conflict Bats and Python cases covered by Go tests #906
• Remove non-owner preflight, start and status fallbacks after N-2 #907
• Remove non-owner continuation, verification and scanner fallbacks after N-2 #908
• Remove non-owner conflict shell and Python fallbacks after N-2 #909

Out of scope

The guard hooks and their replacement (#328), the shared library and
launcher (#321), readiness (#322), and the pull request and merge
transactions (#323, #324).

No child changes an owner or constitutional path. The existing
protected guard paths are deleted only by the single cutover under
#588, with the owner's exact-head review, and this epic does not wait
on it.

Owner

tbhb-dev/devtools