fix(agent): make the tooling's own tests hold in a product checkout

[agjs]

Summary

Three of bun test tools/agent failed in the first product built on the template (Tinkercaster), for reasons unrelated to that product's code:

• Generator tests created a Projects resource, which the product already owns. They now take the first free name from a candidate list (fixtureResourceNames), and withoutRecordAccountPredicate takes the table name instead of assuming projects.
• The generator itself broke once a checkout had a few subjects: Prettier formats a wrapped union with leading pipes, and splicing X | after SubjectInstance = produced X | | Y, which validateEdit rejected. addSubjectInstance rebuilds the union from its members; a test covers both layouts, the duplicate-subject refusal and the anchor checks.
• The pre-push regression asserts the exact compose profile list but pinned only two of the five optional overlays; a product with WITH_MAILPIT=1/WITH_BULLMQ=1 in compose/.env added their profiles. That step now pins all five off, matching its own comment.

Test plan

• bun run agent:check: 87 tests, zero failures, on the template.
• The same files copied into Tinkercaster: its bun test tools/agent goes from 3 failures to zero (verified in that checkout).
• The regression script also caught a real bug in Tinkercaster's locally patched dev.sh, which is being replaced by the template's compose-level tracing defaults.