fix: send only function source to testgen review/repair, not entire module

The review and repair endpoints were receiving the full module source code
as function_source_code, causing prompt overflow (210k > 200k token limit)
for large files. Extract just the function using existing line number info.

Author: KRRT7

codeflash/optimization/function_optimizer.py

@@ -2026,11 +2026,18 @@ def review_and_repair_tests(
                         "unexecuted_branches": dc.unexecuted_branches,
                     }
 
+            # Extract just the function source (not the entire module) for the review prompt
+            func = self.function_to_optimize
+            source_lines = self.function_to_optimize_source_code.splitlines(keepends=True)
+            func_start = (func.doc_start_line or func.starting_line or 1) - 1
+            func_end = func.ending_line or len(source_lines)
+            function_only_source = "".join(source_lines[func_start:func_end])
+
             console.rule()
             with progress_bar("Reviewing generated tests for quality issues..."):
                 review_results = self.aiservice_client.review_generated_tests(
                     tests=tests_for_review,
-                    function_source_code=self.function_to_optimize_source_code,
+                    function_source_code=function_only_source,
                     function_name=self.function_to_optimize.function_name,
                     trace_id=self.function_trace_id,
                     coverage_summary=coverage_summary,
@@ -2089,7 +2096,7 @@ def review_and_repair_tests(
                     repair_result = self.aiservice_client.repair_generated_tests(
                         test_source=gt.generated_original_test_source,
                         functions_to_repair=review.functions_to_repair,
-                        function_source_code=self.function_to_optimize_source_code,
+                        function_source_code=function_only_source,
                         function_to_optimize=self.function_to_optimize,
                         helper_function_names=[f.fully_qualified_name for f in code_context.helper_functions],
                         module_path=Path(self.original_module_path),