Add init debugging support

This adds Delve into the initramfs and a conditional hook which attaches Delve to our init
after the network is up. This allows for breakpoint-debugging the init itself, at least after the
very early node bringup.

Test Plan:
`bazel run -c dbg //:launch`, then use IDEA's Go Remote target to connect to localhost:2345
and set a breakpoint.

Bug: T786

X-Origin-Diff: phab/D581
GitOrigin-RevId: f6b32e7b7f4d36c8492df3e11ee97588817dbd8e
diff --git a/core/cmd/init/BUILD.bazel b/core/cmd/init/BUILD.bazel
index 1e5db46..af37ea6 100644
--- a/core/cmd/init/BUILD.bazel
+++ b/core/cmd/init/BUILD.bazel
@@ -2,13 +2,18 @@
 
 go_library(
     name = "go_default_library",
+    # keep
     srcs = [
         "main.go",
         "switchroot.go",
-    ],
+    ] + select({
+        "//core:debug_build": ["debug_enabled.go"],
+        "//conditions:default": ["debug_disabled.go"],
+    }),
     importpath = "git.monogon.dev/source/nexantic.git/core/cmd/init",
     visibility = ["//visibility:private"],
     deps = [
+        "//core/internal/common:go_default_library",  # keep
         "//core/internal/common/supervisor:go_default_library",
         "//core/internal/network:go_default_library",
         "//core/internal/node:go_default_library",