Reuse terminals for non-service scripts and track lifecycle via OSC 633

Scripts launched from the UI now run in a dedicated terminal per script
(titled after the script) and reuse the same terminal across re-runs.
Script lifecycle is driven by a new onCommandFinished signal sourced from
OSC 633 command-finished events emitted by the zsh shell integration, so
foreground script exit updates status without killing the terminal.
Script payloads now carry terminalId so the workspace can surface the
associated tab from the scripts dropdown.

packages/server/src/shared/messages.ts

@@ -1991,6 +1991,7 @@ export const WorkspaceScriptPayloadSchema = z.object({
   lifecycle: WorkspaceScriptLifecycleSchema,
   health: WorkspaceScriptHealthSchema.nullable(),
   exitCode: z.number().nullable().optional().default(null),
+  terminalId: z.string().nullable().optional().default(null),
 });
 
 const WorkspaceGitRuntimePayloadSchema = z