Removes unused commands from CLI docs

Updates the CLI documentation to reflect the current set of implemented commands.

The 'dev' command no longer includes 'preflight' and 'validate' subcommands.
Removes these commands from the valid commands list.

tinytorch/tools/dev/validate_cli_docs.py

@@ -36,7 +36,7 @@ VALID_COMMANDS: Dict[str, List[str]] = {
     "logo": [],  # No subcommands
     "system": ["info", "health", "jupyter", "update", "logo"],
     "module": ["start", "view", "resume", "complete", "test", "reset", "status", "list"],
-    "dev": ["preflight", "export", "validate"],
+    "dev": ["test", "export"],
     "src": ["export", "test"],
     "package": ["reset", "nbdev"],
     "nbgrader": ["init", "generate", "release", "collect", "autograde", "feedback", "status", "analytics", "report"],