Switch to bun

Remove @vercell/ncc, bun build seems to be reproducible.

BUILD.bazel

@@ -16,22 +16,23 @@ genrule(
     cmd = """
     set -euo pipefail
     # provide a writable home dir
-    export HOME=`pwd`
+    export HOME="$$(pwd)/NOHOME"
+    mkdir "$$HOME"
     # index.js should not be a symlink
     cat index.js > i.js && mv i.js index.js
-    NPM=$(location @nodejs//:bin/npm)
-    "$$NPM" ci
-    "$$NPM" exec -- @vercel/ncc build index.js -o $(RULEDIR)/generated --no-cache
+    BUN=$(location @bun//:bin/bun)
+    $$BUN install --no-save
+    $$BUN build --target=node --outfile=$@ index.js
     """,
-    srcs = ["package.json", "package-lock.json", "index.js"],
+    srcs = ["package.json", "bun.lockb", "index.js"],
     tags = ["requires-network"],
-    tools = ["@nodejs//:bin/npm"],
-    outs = ["generated/index.js"],
+    tools = ["@nodejs//:bin/npm", "@bun//:bin/bun"],
+    outs = ["generated/bundle.mjs"],
     visibility = ["//:__subpackages__"],
 )
 
 updatesrc_diff_and_update(
     name = "update",
-    srcs = ["dist/index.js"],
+    srcs = ["dist/bundle.mjs"],
     outs = [":dist"],
 )

MODULE.bazel

@@ -30,3 +30,9 @@ nix_pkg.attr(
     repo = "@nixpkgs",
 )
 use_repo(nix_pkg, "nodejs")
+
+nix_pkg.attr(
+    attr = "bun",
+    repo = "@nixpkgs",
+)
+use_repo(nix_pkg, "bun")