feat(sdk): add HttpApi clients and embedded host (#33445)

packages/client/README.md

@@ -0,0 +1,27 @@
+# @opencode-ai/client
+
+Private generation target for clients derived directly from OpenCode's authoritative Effect `HttpApi`.
+
+## Entrypoints
+
+- `@opencode-ai/client`: zero-Effect Promise client using `fetch`.
+- `@opencode-ai/client/effect`: rich Effect network client using an environment-provided `HttpClient`.
+
+The generated surface starts with the Session group from Server's concrete API. The build compiler reads `@opencode-ai/server/api`; the generated Effect runtime imports a client-local projection built from Protocol, with a generation-equivalence test preventing transport drift. Run `bun run generate` after changing the contract and `bun run check:generated` to detect committed-output drift.
+
+The Effect entrypoint uses canonical decoded values such as `Session.ID`, `Location.Ref`, and `Prompt`. These datatypes come from the lightweight `@opencode-ai/schema` package and are re-exported so callers depend only on the client surface. Protocol owns endpoint construction and middleware placement; Server supplies the concrete middleware keys used by the build-time API.
+
+The Promise root remains structural and has no Core or Effect runtime dependency. `/effect` depends only on Effect, Schema, and Protocol and is browser-bundle safe. Bundle-boundary tests enforce both import graphs.
+
+Effect consumers construct canonical decoded inputs:
+
+```ts
+import { AbsolutePath, Location, OpenCode, Prompt } from "@opencode-ai/client/effect"
+
+const client = yield * OpenCode.make({ baseUrl: "https://opencode.example" })
+yield *
+  client.sessions.create({
+    location: Location.Ref.make({ directory: AbsolutePath.make("/workspace") }),
+  })
+yield * client.sessions.prompt({ sessionID, prompt: Prompt.make({ text: "Hello" }) })
+```