refactor(protocol): extract server contracts (#33708)

packages/server/src/handlers/session.ts

@@ -2,7 +2,7 @@ import { SessionV2 } from "@opencode-ai/core/session"
 import { DateTime, Effect } from "effect"
 import { HttpApiBuilder, HttpApiSchema } from "effect/unstable/httpapi"
 import { Api } from "../api"
-import { SessionsCursor } from "../groups/session"
+import { SessionsCursor } from "@opencode-ai/protocol/groups/session"
 import {
   ConflictError,
   InvalidCursorError,
@@ -10,7 +10,7 @@ import {
   ServiceUnavailableError,
   SessionNotFoundError,
   UnknownError,
-} from "../errors"
+} from "@opencode-ai/protocol/errors"
 import { AbsolutePath } from "@opencode-ai/core/schema"
 
 const DefaultSessionsLimit = 50