Make roaming an opt-in goose-cli feature (default-off, stays in-tree) (#11516)

Signed-off-by: Michael Neale <michael.neale@gmail.com>
Co-authored-by: Michael Neale <14976+michaelneale@users.noreply.github.com>
Co-authored-by: pstayets <philip@vulturelabs.com>
Co-authored-by: pstayet <philipstayetski2416@gmail.com>
Co-authored-by: Colin Gauvin <colin@gauvin.id>

.github/scripts/repair-v8-prebuilt.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+# v8-goose downloads a prebuilt librusty_v8 archive into target/<profile>/gn_out
+# and emits a rustc-link-search pointing at it. Cargo caches that build script
+# output and replays it on later builds instead of re-running the script, but
+# the Rust cache action prunes target/ before saving, so a restored cache can
+# keep the replayed link-search while the 131MB archive is gone. Linking then
+# fails with "could not find native static library `rusty_v8`".
+#
+# Drop the cached build script output whenever a directory it advertises is
+# missing, which forces the script to re-run and download the archive again.
+set -euo pipefail
+
+[ -d target ] || exit 0
+
+find target -type f -path '*/build/v8-goose-*/output' -print0 |
+  while IFS= read -r -d '' output; do
+    while IFS= read -r dir; do
+      [ -n "$dir" ] || continue
+      [ -d "$dir" ] && continue
+      echo "v8-goose build output references missing $dir; forcing a rebuild"
+      rm -rf "$(dirname "$output")"
+      break
+    done < <(sed -n 's/^cargo:rustc-link-search=\(.*\)$/\1/p' "$output")
+  done