fix(core): expose filesystem failures

packages/plugin/src/v2/effect/filesystem.ts

@@ -1,9 +1,25 @@
 import type { FileSystemEntry } from "@opencode-ai/sdk/v2/types"
 import type { Effect } from "effect"
+import type { PlatformError } from "effect/PlatformError"
+
+export type FileSystemError =
+  | PlatformError
+  | {
+      readonly _tag: "FileSystemError"
+      readonly method: string
+      readonly cause?: unknown
+    }
+  | {
+      readonly _tag: "FileSystem.PathError"
+      readonly path: string
+      readonly reason: "lexical_escape" | "symlink_escape" | "not_file" | "not_directory"
+    }
 
 export interface FileSystem {
-  read(input: { readonly path: string }): Effect.Effect<{ readonly content: Uint8Array; readonly mime: string }>
-  list(input?: { readonly path?: string }): Effect.Effect<FileSystemEntry[]>
+  read(input: {
+    readonly path: string
+  }): Effect.Effect<{ readonly content: Uint8Array; readonly mime: string }, FileSystemError>
+  list(input?: { readonly path?: string }): Effect.Effect<FileSystemEntry[], FileSystemError>
   find(input: {
     readonly query: string
     readonly type?: "file" | "directory"

packages/plugin/src/v2/effect/index.ts

@@ -7,7 +7,7 @@ export type { AISDK, AISDKHooks } from "./aisdk.js"
 export type { Catalog, CatalogDraft, CatalogProviderRecord } from "./catalog.js"
 export type { Command, CommandDraft } from "./command.js"
 export type { Event, EventMap } from "./event.js"
-export type { FileSystem } from "./filesystem.js"
+export type { FileSystem, FileSystemError } from "./filesystem.js"
 export type { Integration, IntegrationDraft, IntegrationMethod, IntegrationMethodRegistration } from "./integration.js"
 export type { Location } from "./location.js"
 export type { Npm } from "./npm.js"