bin/gstack-gbrain-supabase-provision (482-line bash) becomes a 26-line
bun-shebang entry over a new importable lib/gbrain-supabase-provision.ts
with an injected-deps seam (fetch/env/stdout/sleep — D7: args, never
env-mutation-before-import). The 33 spawn-per-test cases run in-process
against the same Bun.serve mocks; exactly one spawn smoke keeps the
shebang/CLI/receipt contract covered.
Byte-compat proven by a 25-case differential harness (old bash bin from
git vs new, same mock): stdout, stderr, exit codes identical across all
subcommands, JSON/plain modes, and error paths. Egress receipts stay
per-attempt, receipt-before-send, fail-closed (scanner updated:
SHELL_SINKS -> MODULE_SINKS). No-op sleep injection makes retry/backoff
paths instant.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>