fix(plugins): publish the plugin SDK under the @getpaseo scope

The daemon imports the plugin SDK at runtime, but the workspace was named
@paseo/plugin and marked private, so it was never published. 0.5.0-beta.1
shipped @getpaseo/server depending on a package that does not exist and
`npm install @getpaseo/cli@beta` failed with a 404 for every user.

Two things hid it. sync-workspace-versions only rewrites deps matching
@getpaseo/*, so the "*" range on @paseo/plugin survived untouched into the
published tarball. And `npm pack --dry-run`, which is all release:check and
CI run, lists files without ever resolving the dependency graph.

Renaming to @getpaseo/plugin rather than publishing the old name: @paseo is
not our scope on npm, so that name could never have been published at all.
The rename also brings the package under the version-sync filter, which is
what pins it correctly from here on.

Plugins scaffolded against the old name still import @paseo/plugin. Both
spellings resolve through plugin-sdk-specifiers.ts, tagged COMPAT with a
removal date, so existing plugins keep loading.

This does not repair 0.5.0-beta.1 — a published tarball's dependencies
cannot be changed. The package publishes with the next release.

packages/app/e2e/browser/plugin-workspace-panels.spec.ts

@@ -31,7 +31,7 @@ function isSettledWorkspaceUrl(url: URL): boolean {
 function pluginSource(): string {
   return `import React, { useRef } from "react";
 import { Text, View } from "react-native";
-import { useAgent, useWorkspace } from "@paseo/plugin";
+import { useAgent, useWorkspace } from "@getpaseo/plugin";
 
 function WorkspacePanel({ workspaceId, host, layout }) {
   const workspace = useWorkspace(workspaceId, (value) => ({ id: value.id }));