batch resources hold raw trans backref dereferenced at cleanup - same UAF class as #594 (fbird_batch.c:178/:627)

[satwareAG-ironMike]

Found during PR #598 review (out of scope there).

Problem

`fbird_batch.c:178` stores `fb_batch->trans = trans;` (raw `fbird_transaction*`), dereferenced at :627. The #594 fix added a registry detaching `fbird_query` back-refs before the transaction struct is efree'd (link close / le_trans dtor / execute_auto temps) - batch resources were deliberately left out (same scope decision as #591's BlobWrapper note).

Same failure shape as #594: transaction struct efree'd while a live batch resource holds the pointer -> UAF on later batch ops/shutdown.

Fix direction

Extend the #594 pattern one more holder type: enroll batches in the same per-transaction registry (or a parallel one) and detach at the same 9 sites. The registry helpers (_php_fbird_trans_reg_query/unreg/detach) are typed to fbird_query - either generalize the intrusive list or duplicate minimally.

Acceptance criteria

• Batch backref detached before trans struct efree
• ASAN test covering batch surviving past its transaction's death
• Negative control observed