feat(core): implement V2 session.shell (#35183)

packages/protocol/src/groups/session.ts

@@ -349,6 +349,26 @@ export const makeSessionGroup = <I extends HttpApiMiddleware.AnyId, S>(sessionLo
           }),
         ),
     )
+    .add(
+      HttpApiEndpoint.post("session.shell", "/api/session/:sessionID/shell", {
+        params: { sessionID: Session.ID },
+        payload: Schema.Struct({
+          id: Event.ID.pipe(Schema.optional),
+          command: Schema.String,
+        }),
+        success: HttpApiSchema.NoContent,
+        error: SessionNotFoundError,
+      })
+        .middleware(sessionLocationMiddleware)
+        .annotateMerge(
+          OpenApi.annotations({
+            identifier: "v2.session.shell",
+            summary: "Run shell command",
+            description:
+              "Execute one shell command in the session's working directory. Emits a shell.started event before execution and a shell.ended event with the merged output after.",
+          }),
+        ),
+    )
     .add(
       HttpApiEndpoint.post("session.compact", "/api/session/:sessionID/compact", {
         params: { sessionID: Session.ID },