fix: remove commented code, obvious comments, and move inline import

- Remove useless commented line 'model_max_output already set above'
- Remove self-explanatory comment about max_output_tokens
- Move llm_registry import from line 1667 to top-level in graph.py

Per Nick's review feedback.

autogpt_platform/backend/backend/blocks/llm.py

@@ -541,9 +541,7 @@ async def llm_call(
             )
         prompt = result.messages
 
-    # Calculate available tokens based on context window and input length
     estimated_input_tokens = estimate_token_count(prompt)
-    # model_max_output already set above
     user_max = max_tokens or model_max_output
     available_tokens = max(context_window - estimated_input_tokens, 0)
     max_tokens = max(min(available_tokens, model_max_output, user_max), 1)
@@ -1191,7 +1189,6 @@ class AIStructuredResponseGeneratorBlock(AIBlockBase):
                     or "token limit" in str(e).lower()
                 ):
                     if input_data.max_tokens is None:
-                        # Use resolved model's max_output_tokens (handles fallback correctly)
                         input_data.max_tokens = resolved_max_output or 4096
                     input_data.max_tokens = int(input_data.max_tokens * 0.85)
                     logger.debug(

autogpt_platform/backend/backend/data/graph.py

@@ -28,6 +28,7 @@ from backend.blocks._base import Block, BlockType, EmptySchema
 from backend.blocks.agent import AgentExecutorBlock
 from backend.blocks.io import AgentInputBlock, AgentOutputBlock
 from backend.blocks.llm import LlmModel
+from backend.data import llm_registry
 from backend.integrations.providers import ProviderName
 from backend.util import type as type_utils
 from backend.util.exceptions import GraphNotAccessibleError, GraphNotInLibraryError
@@ -1664,8 +1665,6 @@ async def migrate_llm_models(migrate_to: LlmModel):
                 llm_model_fields[block.id] = field_name
 
     # Get all model slugs from the registry (dynamic, not hardcoded enum)
-    from backend.data import llm_registry
-
     enum_values = list(llm_registry.get_all_model_slugs_for_validation())
 
     # Skip migration if registry is empty (fresh deployment before seeding)