feat: improve documentation quality with real data

- Extract file-level docstrings from Python files (module-level string expressions)
- Use __init__.py docstrings as module doc_summary
- Use file docstrings as file purpose in layout tables (instead of 'Source file')
- Populate module outbound_modules/inbound_modules from import edges (internal only)
- Make filename sanitization consistent (sanitize_for_link matches sanitize_filename)
- Clean up stale .md files from previous runs before generating
- Fill ARCHITECTURE.md template with real layout, modules index, and critical points
- Add file_docstring field to ParsedModule and file_purpose to FileDoc

archdoc-cli/src/commands/generate.rs

@@ -105,6 +105,19 @@ pub fn generate_docs(model: &ProjectModel, out: &str, verbose: bool, _config: &C
     std::fs::create_dir_all(&modules_path)?;
     std::fs::create_dir_all(&files_path)?;
 
+    // Clean up stale files from previous runs
+    for subdir in &["modules", "files"] {
+        let dir = out_path.join(subdir);
+        if dir.exists()
+            && let Ok(entries) = std::fs::read_dir(&dir) {
+            for entry in entries.flatten() {
+                if entry.path().extension().map(|e| e == "md").unwrap_or(false) {
+                    let _ = std::fs::remove_file(entry.path());
+                }
+            }
+        }
+    }
+
     let renderer = archdoc_core::renderer::Renderer::new();
     let writer = archdoc_core::writer::DiffAwareWriter::new();