Log().ExcludingRemoteTrackingRefs() without ForRevision returns no commits, even when HEAD has unpushed work #161

What's wrong

GitLogBuilder emits --not --remotes --not for ExcludingRemoteTrackingRefs() and, when neither ForRevision nor IncludingAllRefs() was called, no revision at all (GitLogBuilder.cs L180-210). The builder's docs say Log() lists commits "from HEAD" by default (L29, L48).

git only falls back to HEAD when no revision input was given. A pseudo-ref option like --remotes counts as input (git sets rev_input_given), even when it is negated or matches nothing. So git log --not --remotes --not lists nothing.

Why it matters

repository.Log().ExcludingRemoteTrackingRefs().ExecuteAsync() is the natural way to ask "what have I not pushed?", and it always returns an empty list. An empty list reads as "nothing unpushed", which is the data-loss answer the method's own remarks warn about. Adding ForPath(...), FirstParentOnly() or Take(...) makes no difference.

Reproduction (git 2.43.0)

git init -q r && cd r
git -c user.name=a -c user.email=a@b commit -q --allow-empty -m one
git log --format=%s --not --remotes --not          # prints nothing
git log --format=%s --not --remotes --not HEAD     # prints "one"

The same thing happens in a clone that has origin/main plus one local-only commit.

Existing tests cover only the IncludingAllRefs() and ForRevision("HEAD") combinations (GitRemoteSyncTests.cs L118-170, GitLogBuilderTests.cs L147-203). The bare call is untested.

Suggested fix

When _excludingRemoteTrackingRefs && !_includingAllRefs && _revision is null, append HEAD through AppendOperands, so the documented default holds. Alternatively, throw InvalidOperationException asking for a revision, but defaulting to HEAD matches the docs.

Acceptance criteria

• Log().ExcludingRemoteTrackingRefs() with no revision returns the commits reachable from HEAD that aren't on any remote-tracking ref.
• Integration tests cover the bare call both with a remote that is behind HEAD and in a repository with no remotes, where every commit should be returned.
• An argv test pins the emitted HEAD operand.