fix(sandbox): canonicalize agent main alias

src/agents/sandbox.resolveSandboxContext.test.ts

@@ -105,6 +105,14 @@ describe("resolveSandboxContext", () => {
       }),
     ).toBeNull();
 
+    expect(
+      await resolveSandboxContext({
+        config: cfg,
+        sessionKey: "agent:main:main",
+        workspaceDir: "/tmp/clawdbot-test",
+      }),
+    ).toBeNull();
+
     expect(
       await ensureSandboxWorkspaceForSession({
         config: cfg,
@@ -113,6 +121,14 @@ describe("resolveSandboxContext", () => {
       }),
     ).toBeNull();
 
+    expect(
+      await ensureSandboxWorkspaceForSession({
+        config: cfg,
+        sessionKey: "agent:main:main",
+        workspaceDir: "/tmp/clawdbot-test",
+      }),
+    ).toBeNull();
+
     expect(spawn).not.toHaveBeenCalled();
 
     vi.doUnmock("node:child_process");