feat: add run() and binary entry points for all servers and init

Every server now has lib.rs (testable) + main.rs (deployable binary).
Binary is 3 lines: extern crate userspace_rt + call run().
Hardware servers use feature flags for adapter selection.
9 RISC-V binaries ready for the disk image.

crates/init/src/lib.rs

@@ -5,3 +5,12 @@ pub mod manifest;
 pub mod protocol_helpers;
 pub mod shutdown;
 pub mod supervisor;
+
+pub fn run() -> ! {
+    let create_cap = types::bounded::CapSlot::new(0)
+        .unwrap_or_else(|| unreachable!());
+
+    let result = boot::boot(&manifest::SNAKE_MANIFEST, create_cap);
+    let mut sup = boot::create_supervisor(&manifest::SNAKE_MANIFEST, &result);
+    sup.run(create_cap);
+}

crates/init/src/main.rs

@@ -0,0 +1,9 @@
+#![no_std]
+#![no_main]
+
+extern crate userspace_rt;
+
+#[unsafe(no_mangle)]
+extern "C" fn main() {
+    init::run();
+}