docs(config_reader[ConfigReader._from_file]) update TODO: vcspull add landed

why: The trigger condition in the TODO ("once the new vcspull add flow
lands") was already satisfied — vcspull add now uses DuplicateAwareConfigReader
for reading. The stale "Revisit once" sentence misled readers into thinking
the integration was still pending.
what:
- Replace the stale "Revisit once the new vcspull add flow lands" sentence
  with a note reflecting the current state
- Note that this basic loader remains for simpler read contexts
- Identify Option 1 (shared utility) as the cleanest long-term path

Author: tony

src/vcspull/_internal/config_reader.py

@@ -164,8 +164,9 @@ def _from_file(cls, path: pathlib.Path) -> dict[str, t.Any]:
         #    the formatter helpers directly;
         # 3) Keep this basic loader but add an opt-in path for duplicate-aware
         #    parsing so commands like ``vcspull add`` can avoid data loss.
-        # Revisit once the new ``vcspull add`` flow lands so both commands share
-        # the same duplication safeguards.
+        # ``vcspull add`` now uses ``DuplicateAwareConfigReader`` for reading
+        # (see ``cli/add.py``). This basic loader remains for simpler read
+        # contexts. Option 1 (shared utility) is the cleanest long-term path.
 
         fmt = config_format_from_path(path)
         if fmt is None: