cmd/git(fix[remote.add]): Wire fetch, track, and master parameters

why: GitRemoteManager.add() exposed fetch, track, master parameters in
the signature but they were never translated to CLI flags. Callers would
get silent no-ops when using these options.
what:
- Wire fetch to -f flag
- Wire track to -t <branch>
- Wire master to -m <master>

Author: tony

src/libvcs/cmd/git.py

@@ -4255,6 +4255,12 @@ def add(
         local_flags: list[str] = []
         required_flags: list[str] = [name, url]
 
+        if fetch is True:
+            local_flags.append("-f")
+        if track is not None:
+            local_flags.extend(["-t", track])
+        if master is not None:
+            local_flags.extend(["-m", master])
         if mirror is not None:
             if isinstance(mirror, str):
                 assert any(f for f in ["push", "fetch"])