src/cli(refactor[add]): remove automatic ./ to tilde migration

why: Path-first adds should not auto-migrate existing ./ sections; explicit --workspace ./ is the only way to create/target ./ labels.
what:
- Remove migration logic from _ensure_workspace_label_for_merge
- Remove migration logic from _prepare_no_merge_items
- Existing ./ sections now preserved when they match the target workspace

refs: Simplify legacy heuristics

Author: tony

src/vcspull/cli/add.py

@@ -461,10 +461,6 @@ def _ensure_workspace_label_for_merge(
             if existing_label is None:
                 workspace_label = preferred_label
                 config_data.setdefault(workspace_label, {})
-            elif existing_label == "./":
-                workspace_label = preferred_label
-                config_data[workspace_label] = config_data.pop("./")
-                relabelled = True
             else:
                 workspace_label = existing_label
 
@@ -509,20 +505,6 @@ def _prepare_no_merge_items(
             target_index = len(items) - 1
             return workspace_label, target_index, relabelled
 
-        found_label: str | None = None
-        for idx in reversed(matching_indexes):
-            current_label = items[idx]["label"]
-            if current_label != "./":
-                found_label = current_label
-                break
-
-        workspace_label = preferred_label if found_label is None else found_label
-
-        for idx in matching_indexes:
-            if items[idx]["label"] == "./" and workspace_label != "./":
-                items[idx]["label"] = workspace_label
-                relabelled = True
-
         target_index = matching_indexes[-1]
         workspace_label = items[target_index]["label"]
         return workspace_label, target_index, relabelled