fix: resolve pyright reportUnusedImport in manifest_extends

Import ManifestError at module level from manifest_util (no circular
dep) and remove the redundant local imports from function bodies that
were shadowing it. ManifestBottle retains its local import pattern to
avoid the circular manifest ↔ manifest_extends dependency.

bot_bottle/manifest_extends.py

@@ -4,6 +4,8 @@ from __future__ import annotations
 
 from typing import TYPE_CHECKING
 
+from .manifest_util import ManifestError
+
 if TYPE_CHECKING:
     from .manifest import ManifestBottle, ManifestGitEntry
     from .manifest_egress import ManifestEgressConfig
@@ -27,8 +29,6 @@ def resolve_bottles_partial(
     collected in `broken` rather than raising, so unrelated bottles remain
     usable. Errors for parent bottles propagate to all children that extend
     them."""
-    from .manifest import ManifestError
-
     cache: dict[str, ManifestBottle] = {}
     broken: dict[str, ManifestError] = {}
     for name in raws:
@@ -43,7 +43,7 @@ def _resolve_one_bottle(
     cache: dict[str, ManifestBottle],
     seen: tuple[str, ...],
 ) -> ManifestBottle:
-    from .manifest import ManifestBottle, ManifestError
+    from .manifest import ManifestBottle
 
     if name in cache:
         return cache[name]
@@ -191,7 +191,7 @@ def _resolve_one_bottle_partial(
     seen: tuple[str, ...],
 ) -> None:
     """Error-tolerant variant: on failure, adds to `broken` instead of raising."""
-    from .manifest import ManifestBottle, ManifestError
+    from .manifest import ManifestBottle
 
     if name in cache or name in broken:
         return