docs: limit structure overview to directories

README.md

@@ -13,11 +13,8 @@ dev/                    Monorepo root
 ├── src/                 Projects
 │   ├── dotfiles/        Home and system configuration
 │   └── machoke/         Rust application
-├── third_party/         External source and vendoring support
+└── third_party/         External source and vendoring support
-│   └── crates/          Generated Rust crate sources and Bazel targets
+    └── crates/          Generated Rust crate sources and Bazel targets
-├── Cargo.lock           Shared Rust dependency lockfile
-├── Cargo.toml           Rust workspace manifest
-└── MODULE.bazel         Bazel module definition
 ```
 
 ## Rust dependencies