feat(codemode): add confined execution package (#35118)

Co-authored-by: opencode-agent[bot] <opencode-agent[bot]@users.noreply.github.com>

packages/codemode/src/values.ts

@@ -0,0 +1,34 @@
+import type { Effect, Fiber } from "effect"
+
+export class SandboxPromise {
+  interrupted = false
+  constructor(
+    readonly fiber: Fiber.Fiber<unknown, unknown> | undefined,
+    readonly immediate?: Effect.Effect<unknown, unknown>,
+  ) {}
+}
+
+export class SandboxDate {
+  constructor(readonly time: number) {}
+}
+
+export class SandboxRegExp {
+  readonly regex: RegExp
+  constructor(pattern: string, flags: string) {
+    this.regex = new RegExp(pattern, flags)
+  }
+}
+
+export class SandboxMap {
+  readonly map = new Map<unknown, unknown>()
+}
+
+export class SandboxSet {
+  readonly set = new Set<unknown>()
+}
+
+export const isSandboxValue = (value: unknown): value is SandboxDate | SandboxRegExp | SandboxMap | SandboxSet =>
+  value instanceof SandboxDate ||
+  value instanceof SandboxRegExp ||
+  value instanceof SandboxMap ||
+  value instanceof SandboxSet