buyer/scripts/monitor-wallets: add buyer-a + buyer-b@vector-modules-simulation

The two mainnet buyer-bot wallets on vector-modules-simulation
(178.105.3.133, SSH user `user`, env files at ~/marketplace-agents/
buyer-{a,b}.env) were missing from OPERATOR_SOURCES so monitor:wallets
didn't report on them.

State at time of discovery (2026-05-20): both BROKEN with the same
fragmentation pattern as the open-webui supplier — 11 and 12 UTxOs
respectively, max 3.00 AP3X, no UTxO ≥ 5 AP3X for collateral.
Cron-driven Accept/Reclaim cycles were failing silently.

Both consolidated to {5 AP3X collateral, ~22 AP3X working, 1.5 AP3X
collateral-return} via the tx:consolidate-wallet CLI (commit 972c0f9)
run inside the vector-marketplace buyer container with --priv-key:
  - buyer-a@vector-modules-simulation
    addr1vytah0zpcn3gn00lvu83g4qur4th0cg02v9hslaqlq9k88g5squ09
    tx b789c2719bcee221f935578b4ac277d96295fa6e240ec2b63e0f4c83efc18cad
  - buyer-b@vector-modules-simulation
    addr1vy2wlyyat59fx572jgecwdmkxze7v65dl9jvg3pulgxudngvlpeau
    tx ee1269be8aa01113db827cf02b6d9ffa0309524fb5cd2d3a9744cab9ef89f923

Total operator wallets monitored: 6 → 8.

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

buyer/scripts/monitor-wallets.ts

@@ -85,6 +85,20 @@ const OPERATOR_SOURCES: OperatorSource[] = [
     keyVar: "SUPPLIER_PRIV_KEY_HEX",
     role: "supplier",
   },
+  {
+    label: "buyer-a@vector-modules-simulation",
+    host: "user@178.105.3.133",
+    envPath: "/home/user/marketplace-agents/buyer-a.env",
+    keyVar: "BUYER_PRIV_KEY_HEX",
+    role: "buyer",
+  },
+  {
+    label: "buyer-b@vector-modules-simulation",
+    host: "user@178.105.3.133",
+    envPath: "/home/user/marketplace-agents/buyer-b.env",
+    keyVar: "BUYER_PRIV_KEY_HEX",
+    role: "buyer",
+  },
 ];
 
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