feat: add directory-scoped host defaults (match_dirs) and repo list --limit

Add match_dirs field to host config entries for directory-based host
resolution. When no --hostname flag, FGJ_HOST env var, or git remote is
detected, the longest matching directory prefix determines the host.
Symlinks are resolved on both sides for macOS compatibility (/tmp →
/private/tmp). Also adds --limit/-L flag to repo list.

internal/api/client_test.go

@@ -21,7 +21,7 @@ func TestNewClientFromConfig_MissingHost(t *testing.T) {
 		Hosts: map[string]config.HostConfig{},
 	}
 
-	_, err := NewClientFromConfig(cfg, "nonexistent.org", "")
+	_, err := NewClientFromConfig(cfg, "nonexistent.org", "", "")
 	if err == nil {
 		t.Error("Expected error for nonexistent host")
 	}