feat: implement all P1/P2/P3/P4 improvements from issue backlog

P1 correctness:
- filter test files by default (--include-tests to opt in)
- per-module diagrams show cross-module dependency arrows
- qualified type names (Module::TypeName) fix false edges from duplicate names

P2 output richness:
- method parameter types and return types in class diagrams (Rust + Python)
- Python pyproject.toml project analyzer (--level project for monorepos)

P3 unique value:
- boundary rules in archlens.toml ([rules] allow/deny, --strict enforcement)

P4 nice to have:
- dependency weight labels on module arrows (--no-weights to disable)
- --watch mode with 500ms debounce
- D2 renderer adapter (--format d2)
- interactive self-contained HTML viewer (--format html)
- git-aware incremental analysis (--since <ref>)

crates/presentation/tests/end_to_end_tests.rs

@@ -53,6 +53,10 @@ fn analyzes_rust_project_and_writes_mermaid_to_file() {
         config: None,
         scope: None,
         exclude: vec![],
+        include_tests: false,
+        no_weights: false,
+        watch: false,
+        since: None,
         split_by_module: false,
         strict: false,
         check: false,
@@ -83,6 +87,10 @@ fn works_without_config_file() {
         config: None,
         scope: None,
         exclude: vec![],
+        include_tests: false,
+        no_weights: false,
+        watch: false,
+        since: None,
         split_by_module: false,
         strict: false,
         check: false,
@@ -108,6 +116,10 @@ fn split_by_module_writes_overview_and_per_module_files() {
         config: None,
         scope: None,
         exclude: vec![],
+        include_tests: false,
+        no_weights: false,
+        watch: false,
+        since: None,
         split_by_module: true,
         strict: false,
         check: false,
@@ -131,3 +143,59 @@ fn split_by_module_writes_overview_and_per_module_files() {
         "should have overview + at least one module file"
     );
 }
+
+fn create_cross_module_project(dir: &std::path::Path) {
+    fs::create_dir_all(dir.join("src/app")).unwrap();
+    fs::create_dir_all(dir.join("src/domain")).unwrap();
+    fs::write(
+        dir.join("src/domain/order.rs"),
+        "pub struct Order { pub id: u64 }\n",
+    )
+    .unwrap();
+    fs::write(
+        dir.join("src/app/service.rs"),
+        "use crate::domain::Order;\npub struct OrderService { order: Order }\n",
+    )
+    .unwrap();
+}
+
+#[test]
+fn per_module_file_shows_cross_module_dependency_arrows() {
+    let project = tempfile::tempdir().unwrap();
+    create_cross_module_project(project.path());
+
+    let output_dir = tempfile::tempdir().unwrap();
+
+    run(archlens::CliArgs {
+        command: None,
+        path: project.path().to_path_buf(),
+        level: "type".to_string(),
+        format: "mermaid".to_string(),
+        output: Some(output_dir.path().to_str().unwrap().to_string()),
+        config: None,
+        scope: None,
+        exclude: vec![],
+        include_tests: false,
+        no_weights: false,
+        watch: false,
+        since: None,
+        split_by_module: true,
+        strict: false,
+        check: false,
+        verbose: 0,
+    })
+    .unwrap();
+
+    let app_file = output_dir.path().join("app.mmd");
+    assert!(app_file.exists(), "app.mmd should exist");
+
+    let content = fs::read_to_string(&app_file).unwrap();
+    assert!(
+        content.contains("<<module>>"),
+        "per-module file should contain external module placeholder: {content}"
+    );
+    assert!(
+        content.contains("domain"),
+        "per-module file should reference the domain module: {content}"
+    );
+}