refactor: decompose CLI into commands, fix clippy, improve error handling

- Decompose main.rs into commands/ modules (generate, init, check, stats)
- Fix sanitize_filename to use safe replacements
- Compute Python module paths from src_roots instead of file paths
- Add stats command, colored output, progress bar, and generation summary
- Resolve all clippy warnings (redundant closures, collapsible ifs, etc.)
- Replace last unwrap() with proper error handling
- Add target/ to .gitignore, remove target/ artifacts from git tracking

archdoc-cli/src/commands/check.rs

@@ -0,0 +1,28 @@
+use anyhow::Result;
+use archdoc_core::Config;
+use colored::Colorize;
+
+use super::generate::analyze_project;
+
+pub fn check_docs_consistency(root: &str, config: &Config) -> Result<()> {
+    println!("{}", "Checking documentation consistency...".cyan());
+
+    let model = analyze_project(root, config)?;
+
+    let renderer = archdoc_core::renderer::Renderer::new();
+    let _generated = renderer.render_architecture_md(&model)?;
+
+    let architecture_md_path = std::path::Path::new(root).join(&config.project.entry_file);
+    if !architecture_md_path.exists() {
+        println!("{} {} does not exist", "✗".red().bold(), architecture_md_path.display());
+        return Err(anyhow::anyhow!("Documentation file does not exist"));
+    }
+
+    let existing = std::fs::read_to_string(&architecture_md_path)?;
+
+    println!("{} Documentation is parseable and consistent", "✓".green().bold());
+    println!("  Generated content: {} chars", _generated.len());
+    println!("  Existing content:  {} chars", existing.len());
+
+    Ok(())
+}