feat(builder): query CI via project status script

When BUILD_VENUE=ci, init confirms tea/glab/gh/curl (or a custom
command) and writes .pouch/builder/ci-status.sh. wait_ci.sh only
polls that script and no longer guesses forge CLIs.

skills/builder/scripts/obtain.sh

@@ -10,14 +10,13 @@ set -euo pipefail
 #
 # BUILD_VENUE (makefile.builder, default local):
 #   local  HEAD must be SHA; run `make -f makefile.builder docker` or `deb`
-#   ci     wait for the forge pipeline of this SHA, then inspect the image
-#          (GitHub Actions, GitLab CI, or Gitea Actions)
+#   ci     wait for this SHA via the project CI_STATUS_SCRIPT, then inspect the image
 #
 # Exit:
 #   0  artifact verified; prints ARTIFACT= / DIGEST= / SHA= / VENUE=
 #   1  no pipeline, job failed, inspect failed
 #   2  usage / config
-#   3  forge CLI cannot read the project (ci venue)
+#   3  CI status script cannot query (ci venue)
 
 usage() {
   sed -n '2,20p' "$0"