Rename codebook to methodology report

- Rename function from generate_codebook_pdf to generate_methodology_report_pdf
- Update PDF title to "CatLLM Methodology Report"
- Update file suffix to _methodology_report.pdf
- Update UI label to "Download Results (CSV + Methodology Report)"

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app.py

@@ -60,17 +60,17 @@ def is_free_model(model, model_tier):
     return model_tier == "Free Models"
 
 
-def generate_codebook_pdf(categories, model, column_name, num_rows, model_source, filename, success_rate,
+def generate_methodology_report_pdf(categories, model, column_name, num_rows, model_source, filename, success_rate,
                           result_df=None, processing_time=None, prompt_template=None,
                           data_quality=None, catllm_version=None, python_version=None):
-    """Generate a PDF codebook explaining the output columns with comprehensive documentation."""
+    """Generate a PDF methodology report for reproducibility and transparency."""
     from reportlab.lib.pagesizes import letter
     from reportlab.lib import colors
     from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
     from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, PageBreak
 
     # Create temp file for PDF
-    pdf_file = tempfile.NamedTemporaryFile(mode='wb', suffix='_codebook.pdf', delete=False)
+    pdf_file = tempfile.NamedTemporaryFile(mode='wb', suffix='_methodology_report.pdf', delete=False)
     doc = SimpleDocTemplate(pdf_file.name, pagesize=letter)
     styles = getSampleStyleSheet()
 
@@ -83,7 +83,7 @@ def generate_codebook_pdf(categories, model, column_name, num_rows, model_source
     story = []
 
     # === PAGE 1: Title, Category Mapping, Sample Results ===
-    story.append(Paragraph("CatLLM Classification Codebook", title_style))
+    story.append(Paragraph("CatLLM Methodology Report", title_style))
     story.append(Paragraph(f"Generated: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}", normal_style))
     story.append(Spacer(1, 15))
 
@@ -516,7 +516,7 @@ def classify_data(spreadsheet_file, spreadsheet_column,
             result.to_csv(f.name, index=False)
             csv_path = f.name
 
-        # Get original filename for codebook
+        # Get original filename for methodology report
         original_filename = file_path.split("/")[-1]
 
         # Calculate success rate
@@ -539,8 +539,8 @@ is the key and a 1 if the category is present and a 0 if not.'''
             catllm_version = "unknown"
         python_version = sys.version.split()[0]
 
-        # Generate PDF codebook with all new data
-        pdf_path = generate_codebook_pdf(
+        # Generate PDF methodology report with all new data
+        pdf_path = generate_methodology_report_pdf(
             categories=categories,
             model=actual_model,
             column_name=spreadsheet_column,
@@ -800,7 +800,7 @@ https://github.com/chrissoria/cat-llm
             )
             sample_results = gr.DataFrame(label="Sample Results (First 5 Rows)", visible=False)
             results = gr.DataFrame(label="Full Classification Results", visible=False)
-            download_file = gr.File(label="Download Results (CSV + Codebook PDF)", file_count="multiple")
+            download_file = gr.File(label="Download Results (CSV + Methodology Report)", file_count="multiple")
             code_output = gr.Code(
                 label="Python Code",
                 language="python",