Automate boot unit inclusion with architecture-aware Moderne analysis

- Replace boot.mgr's static unit list with generated dangling_units.inc
- Generate Pascal LSTs and run the dangling-unit recipe before compilation
- Exclude Wasuro, inactive architectures, and NOT_DANGLING units
- Add ASURO_ARCH selection with an x86 default
- Mark unfinished legacy units as NOT_DANGLING
- Inherit pinned Moderne tooling in the builder image
- Ensure Drone pulls the latest builder image
- Document the updated build pipeline in MkDocs

Validation:
- Full x86 ISO build and VirtualBox boot succeeded
- 1,133 kernel tests passed with no failures
- x86_64 build failed clearly due to unavailable sources

readme.md

@@ -28,7 +28,8 @@ We welcome everyone to give building/breaking/fixing/shooting Asuro a go, feel f
 4. Install Git for Windows.
 5. Install VSCode & the listed plugins.
 6. Install VirtualBox (v7+).
-7. Clone this repository.
+7. Clone this repository. The builder inherits the published Moderne/Pascal
+   tooling image; see [boot-unit generation](doc/toolchain/dangling_units.md).
 8. Run the following command in the root of the repo to build the docker image:
     ```powershell
     docker compose build builder