v0.9.2 - push-commits honors the requested branch

[0.9.2] - 2026-09-04

In plain terms: even after fixing the client so it remembers which
branch you actually checked out, the server side of deltix push was still
always writing pushed commits onto its default branch (main) no matter
which branch the client said it was pushing from. If your project used a
different working branch (for example sync-develop-base), your pushes
were quietly landing on the wrong branch on the server — which, combined
with the client-side bug already fixed in Deltix-Client v0.8.8, is the full
root cause of the "branch disappeared" incident reported in issue #57.
Fixed: the server now checks out and imports onto the branch the client
actually asks for.

Fixed

• POST /repos/:repoId/push-commits now accepts an optional branch
  field in its request body and forwards it through
  CommitImportService.importCommits() to runDoltCommitImport(), which
  now runs dolt checkout <branch> before importing/committing — instead
  of always operating on whatever branch happened to be checked out
  server-side (effectively always main). Older clients that omit branch
  keep the previous behavior unchanged (backward compatible).
• Non-fast-forward detection (from) now compares against the head of
  the requested branch, not always main — runDoltBranchHead() was
  already branch-aware; it just was never called with anything but the
  default before.
• Paired fix with Deltix-Client v0.8.8, which stopped hardcoding main
  for pull/push/fetch on the client side and started sending the
  project's actual bound branch. Both sides needed the fix: the client fix
  alone would have made push send the right branch, but the server would
  have kept silently ignoring it and importing onto main anyway.

Tests

• New unit tests in commit-import.service.test.ts verify
  importCommits() forwards the client-requested branch to the commit
  runner (instead of relying on a hardcoded default) and that the
  fast-forward check reads the head of that same branch. Full existing
  unit (285 tests) and integration (231 tests, real Dolt binary + real
  HTTP via Hono) suites re-run clean with no regressions.