feat: update version to 0.6.7, enhance build configuration, and add dcr tree command

docs/reference-and-help/cli-reference.md

@@ -7,9 +7,11 @@ dcr new <name>
 dcr init
 dcr setup
 dcr add <name> <source>(optional)
-dcr build [--debug|--release]
+dcr build [--debug|--release] [--target <triple>]
 dcr run [--debug|--release]
 dcr clean [--debug|--release] [--all]
+dcr tree
+dcr test
 dcr gen <subcommand>
 dcr --help
 dcr --version
@@ -23,6 +25,8 @@ dcr --update
 - `init` and `--update` do not accept extra arguments.
 - `clean` accepts `--debug|--release` and optional `--all`.
 - `gen` supports `project-info`, `compile-commands`, `vscode`, `clion`.
+- `tree` shows a dependency tree (similar to `cargo tree`).
+- `test` / `tests` runs the project's tests.
 
 ## Exit behavior overview