fix(fetchium): Fix declaration emit and rest subpath for downstream consumers (#1)

* fix(fetchium): Export TypeDefSymbol for declaration emit

Export `TypeDefSymbol` from types.ts so downstream consumers can emit
.d.ts files without TS4029 errors when using TypeDef<T> in public type
positions, such as when extending Entity.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix(fetchium): Fix declaration emit for downstream consumers

Replace unique symbol brand with string brand to fix TS4029 errors
during declaration emit in downstream packages. TypeScript's declaration
emitter cannot reference unique symbols across package boundaries
(microsoft/TypeScript#56107), causing "cannot be named" errors for any
consumer compiling with declaration: true.

Also add the rest subpath entry to the Vite build config so that
fetchium/rest produces runtime JS bundles at the paths declared in
package.json exports.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jimmy-phantom

.changeset/export-typedef-symbol.md

@@ -0,0 +1,5 @@
+---
+"fetchium": patch
+---
+
+Export `TypeDefSymbol` so downstream consumers can emit `.d.ts` files without TS4029 errors when using `TypeDef<T>` in public type positions, such as when extending `Entity`.

packages/fetchium/src/typeDefs.ts

@@ -950,7 +950,7 @@ export const t: APITypes = {
   null: Mask.NULL as unknown as TypeDef<null>,
   undefined: Mask.UNDEFINED as unknown as TypeDef<undefined>,
   array: defineArray,
-  object: defineObject,
+  object: defineObject as APITypes['object'],
   record: defineRecord,
   union: defineUnion,
   nullish: defineNullish,

packages/fetchium/src/types.ts

@@ -123,14 +123,16 @@ export interface CaseInsensitiveEnumSet<T extends string | boolean | number> ext
 // Public Branded TypeDef
 // ================================
 
-declare const TypeDefSymbol: unique symbol;
-
 /**
  * Branded phantom type representing a type definition in the public API.
  * At runtime, values are Masks, Sets, ValidatorDefs, etc. but the type system
  * sees them as TypeDef<T> where T is the extracted TypeScript type.
+ *
+ * Uses a string brand instead of unique symbol to avoid TS4029 errors
+ * during declaration emit in downstream packages.
+ * See: https://github.com/microsoft/TypeScript/issues/56107
  */
-export type TypeDef<T = unknown> = T & { readonly [TypeDefSymbol]: T };
+export type TypeDef<T = unknown> = T & { readonly __fetchiumTypeDef: T };
 
 // ================================
 // Internal Type Definitions

packages/fetchium/vite.config.ts

@@ -20,6 +20,7 @@ export default defineConfig({
         'stores/sync': resolve(__dirname, 'src/stores/sync.ts'),
         'subscriptions/polling': resolve(__dirname, 'src/subscriptions/polling.ts'),
         'topic/index': resolve(__dirname, 'src/topic/index.ts'),
+        'rest/index': resolve(__dirname, 'src/rest/index.ts'),
       },
       formats: ['es', 'cjs'],
     },