docs(skills): field-types rule states a formula's five returnType members and the currencyConfig a currency formula carries

The objectstack-data field-types rule taught returnType as a four-member set
and its formula example said (no 'currency'); @objectstack/spec declares five
members, and a 'currency' formula carries its own currencyConfig. Both sites
now state the five-member set and name the carrier. The example's CEL comment,
which restated the table cell, is removed to pay the skill token ratchet.

Co-authored-by: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011u73oxZ5X95qrARPTeoU6v

Author: claude

.changeset/22743-field-types-currency-returntype.md

@@ -0,0 +1,9 @@
+---
+'@objectstack/skills': patch
+---
+
+fix(skills): the `objectstack-data` field-types rule names all five formula `returnType` members, `'currency'` included, and the `currencyConfig` a currency formula carries (#22743)
+
+Clause-②: no
+
+`skills/objectstack-data/rules/field-types.md` taught a formula's `returnType` as the four-member set `'number' | 'text' | 'boolean' | 'date'`, and its formula example said `(no 'currency')`. `@objectstack/spec`'s `FieldSchema.returnType` is the five-member enum `'number' | 'text' | 'boolean' | 'date' | 'currency'`, and a formula whose `returnType` is `'currency'` carries its currency in its own `currencyConfig` — `CurrencyConfigSchema`, the same shape a `currency` field declares; absent, the mode is `dynamic`, the tenant default currency. The `formula` table row and the formula example now both state the five-member set and name `currencyConfig` as the carrier. The example's `CEL — record. prefixes required` comment, which restated the table cell above it, is removed to pay the skill's token ratchet. Nothing is said about how a currency formula renders.

skills/objectstack-data/rules/field-types.md

@@ -126,7 +126,7 @@ Stored as JSON on the parent row — no separate table / FK:
 
 | Type | When to Use | Config |
 |:-----|:------------|:-------|
-| `formula` | Computed from an expression referencing other fields | `expression` (CEL, `record.` prefixes), `returnType` (`'number' \| 'text' \| 'boolean' \| 'date'`) |
+| `formula` | Computed from an expression referencing other fields | `expression` (CEL, `record.` prefixes), `returnType` (`'number' \| 'text' \| 'boolean' \| 'date' \| 'currency'`); `'currency'` carries its own `currencyConfig` |
 | `summary` | Roll-up aggregation from child records | `summaryOperations` ({ object, field, function, relationshipField?, filter? }) |
 | `autonumber` | Auto-incrementing display format ({0000} counter + optional date / {field} tokens, resets per scope) | `format` (shorthand) / `autonumberFormat` (canonical) — e.g., `"CASE-{0000}"`, `"AD{YYYYMMDD}{0000}"` |
 
@@ -249,8 +249,8 @@ import { F } from '@objectstack/spec';
 
 const total = {
   type: 'formula',
-  expression: F`record.amount * record.tax_rate`,  // CEL — `record.` prefixes required
-  returnType: 'number',   // 'number' | 'text' | 'boolean' | 'date' (no 'currency')
+  expression: F`record.amount * record.tax_rate`,
+  returnType: 'number',   // 'number' | 'text' | 'boolean' | 'date' | 'currency' (money; own currencyConfig)
 };
 ```