feat(payment): first-class transaction_id when recording a règlement

Make the originating bank transaction id a first-class input on payment-record.sh
so every règlement is tied to the real bank movement at write time.

- `transaction_id` is the canonical field (the Qonto/Wise feed tx id); `num` stays
  as a back-compat alias. It's stored on the payment's bank line (llx_bank.num_chq),
  the reconciliation key.
- Recording WITHOUT a transaction_id prints a stderr warning (still posts, but won't
  auto-reconcile) — nudges the agent to always carry it.
- Output normalises to {id, bank_transaction_id, transaction_id}.
- Promote: manifests' payment ops carry transaction_id; promote-plan shows it
  (tx=… or tx=MISSING).

Proven live: customer + supplier record with transaction_id; the `num` alias maps
to the same field; the no-tx warning fires; promote plan/apply carry it through.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

bin/arcodange

@@ -85,7 +85,7 @@ COMMANDS
   sandbox                            WRITE ops on erp-sandbox ONLY (host-guarded; JSON on stdin)
     thirdparty                                     Create a client/supplier fiche
     invoice                                        Customer/supplier invoice + product/service lines
-    payment                                        Record a règlement (num=bank tx id) → bank_transaction_id
+    payment                                        Record a règlement (transaction_id=bank tx) → bank_transaction_id
     creditnote                                     Create an avoir — customer or supplier (kind)
     accounts                                       List bank accounts (id/label) to pick account_id
     write                <METHOD> <path> [body]    Raw host-guarded write