Fix issue workspace reuse after isolation

Persist realized isolated/operator workspaces back onto the issue as reusable workspaces so later runs stay on the same workspace, and update the issue workspace picker to present realized isolated workspaces as existing workspaces.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/services/heartbeat.ts

@@ -45,6 +45,7 @@ import { workspaceOperationService } from "./workspace-operations.js";
 import {
   buildExecutionWorkspaceAdapterConfig,
   gateProjectExecutionWorkspacePolicy,
+  issueExecutionWorkspaceModeForPersistedWorkspace,
   parseIssueExecutionWorkspaceSettings,
   parseProjectExecutionWorkspacePolicy,
   resolveExecutionWorkspaceMode,
@@ -2098,11 +2099,29 @@ export function heartbeatService(db: Db) {
         cleanupReason: null,
       });
     }
-    if (issueId && persistedExecutionWorkspace && issueRef?.executionWorkspaceId !== persistedExecutionWorkspace.id) {
-      await issuesSvc.update(issueId, {
-        executionWorkspaceId: persistedExecutionWorkspace.id,
-        ...(resolvedProjectWorkspaceId ? { projectWorkspaceId: resolvedProjectWorkspaceId } : {}),
-      });
+    if (issueId && persistedExecutionWorkspace) {
+      const nextIssueWorkspaceMode = issueExecutionWorkspaceModeForPersistedWorkspace(persistedExecutionWorkspace.mode);
+      const shouldSwitchIssueToExistingWorkspace =
+        issueRef?.executionWorkspacePreference === "reuse_existing" ||
+        executionWorkspaceMode === "isolated_workspace" ||
+        executionWorkspaceMode === "operator_branch";
+      const nextIssuePatch: Record<string, unknown> = {};
+      if (issueRef?.executionWorkspaceId !== persistedExecutionWorkspace.id) {
+        nextIssuePatch.executionWorkspaceId = persistedExecutionWorkspace.id;
+      }
+      if (resolvedProjectWorkspaceId && issueRef?.projectWorkspaceId !== resolvedProjectWorkspaceId) {
+        nextIssuePatch.projectWorkspaceId = resolvedProjectWorkspaceId;
+      }
+      if (shouldSwitchIssueToExistingWorkspace) {
+        nextIssuePatch.executionWorkspacePreference = "reuse_existing";
+        nextIssuePatch.executionWorkspaceSettings = {
+          ...(issueExecutionWorkspaceSettings ?? {}),
+          mode: nextIssueWorkspaceMode,
+        };
+      }
+      if (Object.keys(nextIssuePatch).length > 0) {
+        await issuesSvc.update(issueId, nextIssuePatch);
+      }
     }
     if (persistedExecutionWorkspace) {
       context.executionWorkspaceId = persistedExecutionWorkspace.id;