fix(plugin-sdk): remove relative extension boundary escapes (#51939)

* fix(plugin-sdk): remove relative extension boundary escapes

* Gate new plugin-sdk subpaths on host version

* Add changelog entry for #51939

* Fix local staging for plugin-sdk host version gate

* Raise host floor for line and googlechat plugins

---------

Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

extensions/slack/src/runtime-api.ts

@@ -9,7 +9,7 @@ export {
   type ChannelPlugin,
   type OpenClawConfig,
   type SlackAccountConfig,
-} from "../../../src/plugin-sdk/slack.js";
+} from "openclaw/plugin-sdk/slack";
 export {
   listSlackDirectoryGroupsFromConfig,
   listSlackDirectoryPeersFromConfig,
@@ -25,5 +25,5 @@ export {
   readStringParam,
   SlackConfigSchema,
   withNormalizedTimestamp,
-} from "../../../src/plugin-sdk/slack-core.js";
+} from "openclaw/plugin-sdk/slack-core";
 export { isSlackInteractiveRepliesEnabled } from "./interactive-replies.js";