feat: support typed in-process WIP clients without HTTP

MIGRATION.md

@@ -1,5 +1,46 @@
 # Structured Interface reference and scope publication migration
 
+## Transport-independent Client API
+
+The default `wip-client` feature set still exposes the HTTP-compatible
+`wip_client::Client` and `PreparedRequest`. Its constructor takes state and wire
+limits, sessions canonicalize HTTP endpoints, and `complete` consumes an HTTP
+response. Existing TUI and native HTTP consumers need no source migration; the
+wire contract is unchanged.
+
+For an in-process Host (including Client and Host in one WASM module), disable
+default features and use `wip_client::direct::{Client, Request, Response}`:
+
+```toml
+wip-client = { version = "0.2.0", default-features = false }
+```
+
+- `direct::Client::new(ClientLimits)` takes no wire limits.
+- `open_session(worldspace_identity, SecurityContext)` accepts an opaque identity,
+  not a URL. Issue a separate identity per Worldspace view/Host lifetime and a
+  separate security identity whenever authorization context changes. Direct and
+  canonical HTTP session identities cannot alias each other's cache.
+- Preparation methods retain their names and arguments. Their result is
+  `direct::PreparedRequest { id, request: Request }`, with `Observe`,
+  `FetchInterface`, and `CallOperation` variants containing Protocol request DTOs.
+- Route that exact DTO to the session's Host/security context; mark calls
+  dispatched before invoking the Host. Complete with the original `id` and the
+  matching `Response` variant containing `Result<Protocol DTO, ProtocolError>`.
+  No HTTP request, response, JSON codec, or artificial endpoint is needed.
+- Direct responses undergo the same semantic validation and state transitions
+  as HTTP responses. Wrong interactions and invalid results are rejected;
+  invalid call responses retain an unknown execution outcome. Retrievals may
+  be explicitly refreshed, but operations are never automatically retried.
+- `ClientLimits` still bounds cache, sessions, in-flight requests, and history.
+  HTTP status/envelope checks and byte/JSON nesting limits belong to the optional
+  HTTP adapter. An embedding application owns DTO allocation/execution budgets.
+
+The `direct` module API documentation contains a runnable typed example. Run
+`cargo test -p wip-client --no-default-features` to exercise the core without an
+HTTP dependency; ordinary `cargo test -p wip-client` also runs unchanged HTTP
+regressions and direct/HTTP state parity tests.
+
+
 The 0.2.0 API/wire change follows `wip-reference` canonical Core Model,
 Protocol and WIP over HTTP at `6086f3c5ef10aa1464ce9c824750d7f667217bfd`.
 It replaces the earlier opaque Interface reference contract; HTTP routes and