Improve crewai run startup UX (#6297)

Remove redundant startup logs from `crewai run` and make the legacy flow
command warning actionable.

- Stop printing `Running the Flow` and `Running the Crew` before project
  execution.
- Stop printing the redundant `Flow started with ID: ...` line while
  preserving flow lifecycle event emission.
- Replace Click's generic `kickoff` deprecation warning with a clearer
  message that tells users to use `crewai run`.

lib/cli/src/crewai_cli/cli.py

@@ -787,9 +787,13 @@ def flow() -> None:
     """Flow related commands."""
 
 
-@flow.command(name="kickoff", deprecated=True)
+@flow.command(name="kickoff")
 def flow_run() -> None:
     """Kickoff the Flow."""
+    click.secho(
+        "The command 'crewai flow kickoff' is deprecated. Use 'crewai run' instead.",
+        fg="yellow",
+    )
     run_crew(trained_agents_file=None, definition=None, inputs=None)