chore: clean up unused imports and sort import blocks

Remove unused imports and organize import statements to pass ruff
linting checks:

- mcp_server/feature_mcp.py: Remove unused imports (are_dependencies_satisfied,
  get_blocking_dependencies) and alphabetize import block
- parallel_orchestrator.py: Remove unused imports (time, Awaitable) and
  add blank lines between import groups per PEP 8
- server/routers/features.py: Alphabetize imports in dependency resolver

These changes were identified by running `ruff check .` and auto-fixed
with `--fix` flag.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

mcp_server/feature_mcp.py

@@ -37,14 +37,12 @@ from sqlalchemy.sql.expression import func
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
 from api.database import Feature, create_database
-from api.migration import migrate_json_to_sqlite
 from api.dependency_resolver import (
-    would_create_circular_dependency,
-    are_dependencies_satisfied,
-    get_blocking_dependencies,
-    compute_scheduling_scores,
     MAX_DEPENDENCIES_PER_FEATURE,
+    compute_scheduling_scores,
+    would_create_circular_dependency,
 )
+from api.migration import migrate_json_to_sqlite
 
 # Configuration from environment
 PROJECT_DIR = Path(os.environ.get("PROJECT_DIR", ".")).resolve()