add claude skills

.claude/skills/native-monad-result/references/api-surface.md

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+# Result API Surface
+
+These are ALL available methods for Result. Do not use any method not listed here.
+
+## Types
+
+```typescript
+type Result<T, E> = Ok<T> | Err<E>
+type ResultPromise<T, E> = Promise<Result<T, E>>
+type OkPromise<T> = Promise<Ok<T>>
+type ErrPromise<E> = Promise<Err<E>>
+type ResultPartitionResult<T, E> = { values: T[]; errors: E[] }
+```
+
+## Factory Functions
+
+```typescript
+function ok<T>(value: T): Ok<T>
+function err<E>(error: E): Err<E>
+```
+
+## Ok<T> Instance Methods
+
+```typescript
+class Ok<T> {
+  readonly value: T
+
+  isOk(): this is Ok<T>
+  isErr(): this is never
+
+  map<U>(fn: (value: T) => U): Ok<U>
+  mapErr<F>(fn: (error: never) => F): Ok<T>
+
+  flatMap<R extends Result<any, any>>(fn: (value: T) => R): R
+  flatMapErr(): this
+
+  match<U>(onOk: (value: T) => U, onErr: (error: never) => U): U
+
+  // Overload 1: type-narrowing predicate
+  filter<U extends T, F>(predicate: (value: T) => value is U, errorFactory: (value: T) => F): Ok<U> | Err<F>
+  // Overload 2: boolean predicate
+  filter<F>(predicate: (value: T) => boolean, errorFactory: (value: T) => F): Ok<T> | Err<F>
+
+  toNullable(): T
+  toUndefined(): T
+  toString(): string
+}
+```
+
+## Err<E> Instance Methods
+
+```typescript
+class Err<E> {
+  readonly err: E
+
+  isOk(): this is never
+  isErr(): this is Err<E>
+
+  map<U>(): Err<E>
+  mapErr<F>(fn: (error: E) => F): Err<F>
+
+  flatMap(): this
+  flatMapErr<R extends Result<any, any>>(fn: (error: E) => R): R
+
+  match<U>(onOk: (value: never) => U, onErr: (error: E) => U): U
+
+  filter(): Err<E>
+
+  toNullable(): null
+  toUndefined(): undefined
+  toString(): string
+}
+```
+
+## Result Namespace (Static Methods)
+
+```typescript
+Result.from<T, E = unknown>(fn: () => T, errorMap?: (error: unknown) => E): Result<T, E>
+Result.isResult<T, E>(value: unknown): value is Result<T, E>
+Result.all<T>(results: Ok<T>[]): Ok<T[]>
+Result.all<T, E>(results: Result<T, E>[]): Result<T[], E>
+Result.partition<T, E>(results: Result<T, E>[]): ResultPartitionResult<T, E>
+Result.compact<T, E>(results: Result<T, E>[]): T[]
+Result.some<T, E>(results: Result<T, E>[]): boolean
+Result.every<T, E>(results: Result<T, E>[]): boolean
+```
+
+## ResultPromise Namespace (Async Methods)
+
+```typescript
+ResultPromise.from<T, E = unknown>(fn: () => Promise<T>, errorMap?: (error: unknown) => E): ResultPromise<T, E>
+ResultPromise.all<T>(promises: Promise<Ok<T>>[]): Promise<Ok<T[]>>
+ResultPromise.all<T, E>(promises: Promise<Result<T, E>>[]): Promise<Result<T[], E>>
+ResultPromise.partition<T, E>(promises: Promise<Result<T, E>>[]): Promise<ResultPartitionResult<T, E>>
+ResultPromise.compact<T, E>(promises: Promise<Result<T, E>>[]): Promise<T[]>
+ResultPromise.some<T, E>(promises: Promise<Result<T, E>>[]): Promise<boolean>
+ResultPromise.every<T, E>(promises: Promise<Result<T, E>>[]): Promise<boolean>
+```