Fix CI: quote Command forward ref for Python <3.14, revert benchmark.py validation

The `from __future__ import annotations` removal broke pylint on Python
3.10-3.13 because `List[Command]` is a forward reference within the
Command dataclass. Quoting it as `List["Command"]` fixes the issue.

The scaling benchmark.py requires CLI arguments and cannot be validated
as a standalone case file.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

.github/workflows/lint-toolchain.yml

@@ -44,7 +44,7 @@ jobs:
       run: |
         failed=0
         passed=0
-        for case in examples/*/case.py examples/*/benchmark.py; do
+        for case in examples/*/case.py; do
           [ -f "$case" ] || continue
           output=$(./mfc.sh validate "$case" 2>&1)
           if [ $? -eq 0 ]; then

toolchain/mfc/cli/schema.py

@@ -129,7 +129,7 @@ class Command:  # pylint: disable=too-many-instance-attributes
     include_common: List[str] = field(default_factory=list)  # e.g., ["targets", "jobs"]
 
     # Subcommands (for nested commands like "packer pack")
-    subcommands: List[Command] = field(default_factory=list)
+    subcommands: List["Command"] = field(default_factory=list)
 
     # Documentation
     description: Optional[str] = None   # Long description for docs