fix(cli): resolve lint errors and step name conflict in command bus

- Replace deprecated typing imports (Dict, Callable, Generic) with
  collections.abc.Callable and built-in dict
- Convert Command from ABC to plain base class (B024: no abstract methods)
- Convert CommandHandler to PEP 695 type parameter syntax (UP046)
- Remove unused PlanService/ProjectService imports from command_registry
- Fix ruff format: blank line before nested defs in command_registry and steps
- Rename @then('a ValueError should be raised') to domain-specific suffix
  to avoid AmbiguousStep collision with lsp_registry_steps.py

ISSUES CLOSED: #8880

features/cli_command_bus_decoupling.feature

@@ -27,7 +27,7 @@ Feature: CLI Command Bus Decoupling
   Scenario: Dispatch fails for unregistered command
     Given a command bus with no handlers
     When I dispatch a command without a registered handler
-    Then a ValueError should be raised
+    Then a ValueError should be raised for unregistered command dispatch
     And the error message should mention the command type
 
   Scenario: Handler check

features/steps/cli_command_bus_steps.py

@@ -57,6 +57,7 @@ def step_given_command_bus(context):
 @when("I register a handler for a command type")
 def step_register_handler(context):
     """Register a handler for a command type."""
+
     def handler(cmd: TestCommand) -> str:
         return f"Handled: {cmd.value}"
 
@@ -124,7 +125,7 @@ def step_dispatch_unregistered(context):
         context.error = e
 
 
-@then("a ValueError should be raised")
+@then("a ValueError should be raised for unregistered command dispatch")
 def step_value_error_raised(context):
     """Verify a ValueError was raised."""
     assert context.error_raised

src/cleveragents/cli/command_bus.py

@@ -12,14 +12,11 @@ This ensures:
 """
 
 from abc import ABC, abstractmethod
-from typing import Any, Callable, Dict, Generic, TypeVar
-
-# Type variables for command and result
-TCommand = TypeVar("TCommand", bound="Command")
-TResult = TypeVar("TResult")
+from collections.abc import Callable
+from typing import Any
 
 
-class Command(ABC):
+class Command:
     """Base class for all commands dispatched through the command bus.
 
     Commands represent requests from the CLI layer to the application layer.
@@ -29,7 +26,7 @@ class Command(ABC):
     pass
 
 
-class CommandHandler(ABC, Generic[TCommand, TResult]):
+class CommandHandler[TCommand: Command, TResult](ABC):
     """Base class for command handlers.
 
     A handler processes a specific command type and returns a result.
@@ -61,7 +58,7 @@ class CommandBus:
 
     def __init__(self) -> None:
         """Initialize the command bus with an empty handler registry."""
-        self._handlers: Dict[type, Callable[[Any], Any]] = {}
+        self._handlers: dict[type, Callable[[Any], Any]] = {}
 
     def register_handler(
         self, command_type: type, handler: Callable[[Any], Any]

src/cleveragents/cli/command_registry.py

@@ -21,14 +21,6 @@ def register_command_handlers(bus: "CommandBus") -> None:
     Args:
         bus: The CommandBus instance to register handlers with
     """
-    # Import handlers from application services
-    # This is the only place where CLI imports from application services
-    from cleveragents.application.services.plan_service import (
-        PlanService,
-    )
-    from cleveragents.application.services.project_service import (
-        ProjectService,
-    )
 
     # Register handlers for plan commands
     # These handlers wrap service calls and are registered with the bus