feat(rpc): expose snapshot, compare and restore for request versions

Three commands, all host-independent so the browser build answers them from
the same model layer as the desktop:

- models_snapshot_request, for the edit-session boundaries only the frontend
  can see. It takes a reason and nothing else — the caller does not decide
  whether anything changed, because content addressing already has.
- models_request_version, which returns a version and the live request's
  content together so they are guaranteed comparable, plus the same
  content-hash verdict the backend uses rather than a second opinion formed in
  TypeScript.
- models_restore_request_version.

The browser host also snapshots before its own send, since its send pipeline
is in TypeScript rather than in the shared crate.

Bindings regenerated with CI's `cargo test --all --features
yaak-app-client/wry`, which also drops a stale ImportSourceResource from the
rpc-schema copy and adds a missing ImportSource to the plugins copy.

crates/yaak-plugins/bindings/gen_models.ts

@@ -11,6 +11,7 @@ export type AnyModel =
   | HttpRequest
   | HttpResponse
   | HttpResponseEvent
+  | ImportSource
   | KeyValue
   | Plugin
   | Settings
@@ -137,6 +138,10 @@ export type GrpcConnection = {
   state: GrpcConnectionState;
   trailers: { [key in string]?: string };
   url: string;
+  /**
+   * The request version this connection was opened from, when one was captured.
+   */
+  versionId: string | null;
 };
 
 export type GrpcConnectionState = "initialized" | "connected" | "closed";
@@ -241,6 +246,10 @@ export type HttpResponse = {
   state: HttpResponseState;
   url: string;
   version: string | null;
+  /**
+   * The request version this response was sent from, when one was captured.
+   */
+  versionId: string | null;
 };
 
 export type HttpResponseEvent = {
@@ -318,6 +327,18 @@ export type HttpUrlParameter = {
 
 export type HttpVersion = "auto" | "http1" | "http2";
 
+export type ImportSource = {
+  model: "import_source";
+  id: string;
+  createdAt: string;
+  updatedAt: string;
+  workspaceId: string;
+  importer: string;
+  origin: string;
+  originLabel: string;
+  lastImportedAt: string;
+};
+
 export type InheritedBoolSetting = { enabled?: boolean; value: boolean };
 
 export type InheritedHttpVersionSetting = { enabled?: boolean; value: HttpVersion };
@@ -417,6 +438,10 @@ export type WebsocketConnection = {
   state: WebsocketConnectionState;
   status: number;
   url: string;
+  /**
+   * The request version this connection was opened from, when one was captured.
+   */
+  versionId: string | null;
 };
 
 export type WebsocketConnectionState = "initialized" | "connected" | "closing" | "closed";