Pull() rebase conflict raises GitPullConflictException saying "mid-merge"; caller can't tell the repository is actually mid-rebase #242

What's wrong

GitPullBuilder.CreateException (GitIntegration/Builders/GitPullBuilder.cs:288-299) turns any failed pull whose stdout contains CONFLICT into a GitPullConflictException. Its own remarks (lines 280-285) say this covers both merge and rebase conflicts. The exception's documentation (GitIntegration/Execution/GitExceptions.cs:282-297) says "The repository is now mid-merge" and that git exits 128. Neither the exception nor the result says which operation actually stopped.

I reproduced this with git 2.43 using pull --rebase --progress and diverging commits that touch the same line. The result was:

• The exit code is 1, not 128.
• stdout is Auto-merging f / CONFLICT (content): Merge conflict in f.
• The repository is left with .git/rebase-merge and REBASE_HEAD, and there is no MERGE_HEAD.
• status --porcelain=v2 --branch reports # branch.head (detached) plus a u UU entry.
• git merge --abort, which the "mid-merge" wording points the caller to, fails with fatal: There is no merge to abort (MERGE_HEAD missing) (exit 128).

Why it matters

This happens with .Rebase(). It also happens with a plain Pull() on any machine where pull.rebase=true is configured, because Pull() sets no reconciliation mode unless Merge() or Rebase() is called. In that case the caller may not even know a rebase was attempted. Recovery code written from the docs runs merge --abort, which fails and leaves the repository on a detached HEAD in the middle of a rebase.

Suggested fix / acceptance criteria

• GitPullConflictException says which operation stopped, for example through a GitPullConflictKind { Merge, Rebase } property. The kind can be found by checking for REBASE_HEAD / rebase-merge after the failure. Checking the vector for --rebase alone misses the pull.rebase config case.
• The exception remarks no longer claim "mid-merge" unconditionally or "exits 128"
• An integration test in GitRemoteSyncTests covers a Rebase() conflict and asserts the kind
• Another test covers a plain Pull() with pull.rebase=true set in the throwaway repository and asserts the kind