IHS-88: Fix sync_with_git default, set to False

[solababs]

Why

client.branch.create() defaulted sync_with_git to True, while the UI and the infrahubctl branch create CLI both default to False.

This PR aligns the programmatic SDK API with the UI default.

Closes #224

What changed

• Behavioral change: InfrahubBranchManager.create() and InfrahubBranchManagerSync.create() now default sync_with_git to False. Callers that already pass the argument explicitly are unaffected.

Impact & rollout

• Backward compatibility: Breaking change for callers relying on the implicit True default. Changelog entry added (changelog/224.changed.md).

Checklist

• Tests added/updated
• Changelog entry added (changelog/224.changed.md)

---

Summary by cubic

Aligns SDK branch creation default with the UI and CLI by setting sync_with_git to False. Addresses IHS-88 and prevents unexpected Git syncs when creating branches via the SDK.

• Bug Fixes

  • Default sync_with_git=False in InfrahubBranchManager.create() and InfrahubBranchManagerSync.create().

• Migration

  • If you relied on the old implicit True default, pass sync_with_git=True explicitly.

^{Written for commit 876c9d0. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 2 files

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@           Coverage Diff           @@
##           stable    #1025   +/-   ##
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  Coverage   81.54%   81.54%           
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  Files         134      134           
  Lines       11467    11467           
  Branches     1735     1735           
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  Hits         9351     9351           
  Misses       1569     1569           
  Partials      547      547           

Flag	Coverage Δ
integration-tests	41.71% <ø> (ø)
python-3.10	54.59% <ø> (+0.01%)	⬆️
python-3.11	54.59% <ø> (ø)
python-3.12	54.59% <ø> (+0.01%)	⬆️
python-3.13	54.59% <ø> (+0.01%)	⬆️
python-3.14	54.57% <ø> (ø)
python-filler-3.12	22.66% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
infrahub_sdk/branch.py	68.53% <ø> (ø)

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[ajtmccarty]

I think this is technically a breaking change, so would be good to make that a little more clear in the changelog. in the infrahub release notes we have a Breaking Changes section for a release