misc Fast USDC cleanup (#10970)

closes: #9934

## Description
Increases the threshold for multichain that has been timing out (à la #9934)

Also includes a couple tiny improvements to docs and logging.

### Security Considerations


### Scaling Considerations


### Documentation Considerations


### Testing Considerations


### Upgrade Considerations

Author: mergify[bot]

multichain-testing/tools/e2e-tools.js

@@ -23,8 +23,8 @@ import { makeTracer } from '@agoric/internal';
 const trace = makeTracer('E2ET');
 
 // The default of 6 retries was failing.
-// XXX even 15 wasn't enough
-const SMART_WALLET_PROVISION_RETRIES = 30;
+// XXX also tried 15, 30. There's probably something deeper to fix.
+const SMART_WALLET_PROVISION_RETRIES = 100;
 
 const BLD = '000000ubld';
 

packages/fast-usdc/src/exos/transaction-feed.js

@@ -1,7 +1,7 @@
 import { makeTracer } from '@agoric/internal';
 import { prepareDurablePublishKit } from '@agoric/notifier';
 import { keyEQ, M } from '@endo/patterns';
-import { Fail } from '@endo/errors';
+import { Fail, quote } from '@endo/errors';
 import { CctpTxEvidenceShape, RiskAssessmentShape } from '../type-guards.js';
 import { defineInertInvitation } from '../utils/zoe.js';
 import { prepareOperatorKit } from './operator-kit.js';
@@ -221,7 +221,7 @@ export const prepareTransactionFeedKit = (zone, zcf) => {
                   '!=',
                   next,
                 );
-                Fail`conflicting evidence for ${txHash}`;
+                Fail`conflicting evidence for ${quote(txHash)}`;
               }
             }
             lastEvidence = next;

packages/fast-usdc/test/exos/liquidity-pool.test.ts

@@ -2,6 +2,12 @@ import { test } from '@agoric/zoe/tools/prepare-test-env-ava.js';
 
 import { stateShape } from '../../src/exos/liquidity-pool.js';
 
+// NB: We don't test more than this because the Exo has so many runtime dependencies
+// for which we don't have viable mocks.
+// The Exo is tested by fast-usdc.contract.test.js, but that doesn't appear in code coverage.
+// We can solve that by getting code coverage for bundles https://github.com/Agoric/agoric-sdk/issues/1817
+// or by testing without bundling https://github.com/Agoric/agoric-sdk/issues/10558
+
 test('stateShape', t => {
   t.snapshot(stateShape);
 });