Plaid v2 diff harness: three fixes to cut 1246 structural diffs to ~550

1a. Placeholder rule in classifyDiff

v2's composite-graph QLI bodies reference the not-yet-created quote via the SF placeholder @{dealops_new_quote.id} (and child-of-parent QLIs via @{dealops_<n>.id}). SF resolves these at execution time; v1's readback sees the resolved Id. Treat that as semantically equal.

// runPlaidDiffHarness.ts
function classifyDiff(field, v1, v2) {
  // Detection: v2 is a string starting with `@{` and ending with `}`.
  if (typeof v2 === 'string' && v2.startsWith('@{') && v2.endsWith('}')) {
    return 'acceptable';
  }
  if (STRUCTURAL_FIELDS.has(field)) return 'structural';
  // ...rounding-tolerance path follows
}

The rule lives before the structural/rounding dispatch, but only triggers on the exact @{...} shape — partial matches, non-string values, and v1-only mismatches all fall through to the normal classifier.

1b. v1 readback SOQL extension

Six custom fields added to SBQQ_QUOTELINE_FIELDS_TO_READ:

Design choice: extending the SELECT (rather than allowlisting in classifyDiff) keeps future drift visible. If v2 stops emitting one of these, the diff comes back automatically.

The summary boundary was dropping two fields

v1's per-QLI body reads SBQQ__ProductCode__c and SBQQ__Description__c off salesforceProduct.{ProductCode,Description}. v2's loadSalesforceProductsByProduct2Ids previously narrowed the SF row to concern #3/#5/#7 fields and silently dropped these two.

{
  Product2Id,
  CurrencyIsoCode: row.CurrencyIsoCode ?? null,
  extraFields: narrowSalesforceExtraFields(row.extraFields),
  children: [...],
}

{
  Product2Id,
  CurrencyIsoCode: row.CurrencyIsoCode ?? null,
  extraFields: narrowSalesforceExtraFields(row.extraFields),
  ProductCode: row.ProductCode,
  Description: row.Description,
  children: [...] // children also gain ProductCode + Description
}

Emission in buildPlaidQliTailFields

// Empty string === unset (Prisma `@default("")`).
// Emitting "" would create a false-positive diff vs v1's real value.
const productCode =
  sfRow?.ProductCode != null && sfRow.ProductCode !== ''
    ? sfRow.ProductCode : undefined;
const description =
  sfRow?.Description != null && sfRow.Description !== ''
    ? sfRow.Description : undefined;

return {
  ...(extraFields ?? {}),
  CurrencyIsoCode: ...,
  SBCF_Approval_Level__c: approvalLevel ?? 0,
  Order_Form_Product_Name__c: ...,
  SBQQ__RenewedSubscription__c: renewedSubscriptionId ?? null,
  // Declared last so they win on key collision with extraFields.
  SBQQ__ProductCode__c: productCode,
  SBQQ__Description__c: description,
};

Picked up automatically by all three QLI paths — segment, tier, single — because they all flow through this tail helper. Per-tier child QLIs source from the child SF row, not the umbrella (mirrors the existing CurrencyIsoCode plumbing).

Why a backfill, not an emission fix

The diagnostic script queryPlaidCanarySalesforceProductExtraFields.ts (also on this branch) refuted the broader "extraFields is empty" thesis at org level — 100% of canary rows have a populated blob. The matched-pair inspection narrowed it: some products are missing the same 5 keys across all their rows, while others carry them. Field-level partial data, not empty data.

The 5 target keys

Exported as TARGET_EXTRA_FIELD_KEYS and pinned by a test — changing the set without updating the bead is flagged as scope creep.

Merge policy

Safety guards

• Dry-run is the default; --commit is required to write.
• --commit refused when DATABASE_URL === READ_ONLY_DATABASE_URL.
• Reads through prismaReadOnly; SF calls are read-only SOQL.
• SF Id IN (...) queries batched at 200 to stay well under SOQL char limit + 1000-element IN cap.
• dotenv/config imported at the very top so env vars are set before Prisma's eager module-load side effects.

Operator invocation

# Dry-run (default)
npx tsx src/dealops2/scripts/populatePlaidCanarySalesforceProductExtraFields.ts \
  --organization=e846ccc7-40b5-4897-a31b-761d6f51654c

# Commit (operator runs against writable DATABASE_URL after merge)
npx tsx src/dealops2/scripts/populatePlaidCanarySalesforceProductExtraFields.ts \
  --organization=e846ccc7-40b5-4897-a31b-761d6f51654c --commit