fix(auth): cancel stale started flows

Best-effort cancel a running auth flow when its start response arrives after the browser operation was closed or superseded, so sessiond does not retain orphaned provider polling or callback listeners.\n\nRefs #72

.changeset/cancel-stale-auth-flows.md

@@ -0,0 +1,5 @@
+---
+"@jmfederico/pi-web": patch
+---
+
+Cancel auth flows created after their browser start operation becomes stale, preventing abandoned provider polling or callback listeners after the dialog closes.

src/client/src/controllers/authController.test.ts

@@ -191,6 +191,34 @@ describe("AuthController", () => {
     expect(getState().authDialog).toBeUndefined();
   });
 
+  it("best-effort cancels a running flow whose start response arrives after the dialog closes", async () => {
+    const start = deferred<OAuthFlowState>();
+    const provider: AuthProviderOption = { ...authProvider("amazon-bedrock", "api_key"), loginFlow: "interactive" };
+    const cancelCalls: { flowId: string; machineId: string | undefined }[] = [];
+    const { controller, getState } = createController(
+      {
+        selectedMachine: remoteMachine("remote-1"),
+        authDialog: { step: "providers", mode: "login", authType: "api_key", providers: [provider] },
+      },
+      {
+        startInteractiveApiKeyLogin: () => start.promise,
+        cancelOAuthFlow: (flowId, machineId) => {
+          cancelCalls.push({ flowId, machineId });
+          return Promise.reject(new Error("Cancel unavailable"));
+        },
+      },
+    );
+
+    const pendingStart = controller.selectLoginProvider(provider.id, provider.authType);
+    controller.closeDialog();
+    start.resolve(oauthFlow({ flowId: "stale-flow", providerId: provider.id, providerName: provider.name }));
+    await pendingStart;
+
+    expect(cancelCalls).toEqual([{ flowId: "stale-flow", machineId: "remote-1" }]);
+    expect(getState().authDialog).toBeUndefined();
+    expect(getState().error).toBe("");
+  });
+
   it("does not let a stale OAuth response overwrite a newer flow", async () => {
     vi.stubGlobal("window", { setInterval: () => 1, clearInterval: () => undefined });
     const oldPrompt = { requestId: "request-1", message: "Paste callback", kind: "manual" } as const;

src/client/src/controllers/authController.ts

@@ -205,7 +205,18 @@ export class AuthController {
       const flow = provider.authType === "oauth"
         ? await this.api.startOAuthLogin(provider.id, machineId)
         : await this.api.startInteractiveApiKeyLogin(provider.id, machineId);
-      if (operationGeneration !== this.oauthOperationGeneration) return;
+      if (operationGeneration !== this.oauthOperationGeneration) {
+        // Sessiond has already allocated this flow. Do not orphan its timer,
+        // provider polling, or callback listener when the UI operation is stale.
+        if (flow.status === "running") {
+          try {
+            await this.api.cancelOAuthFlow(flow.flowId, machineId);
+          } catch {
+            // Best-effort cleanup; the obsolete flow must not restore UI state.
+          }
+        }
+        return;
+      }
       this.updateOAuthFlow(flow);
       if (flow.status === "running") this.startPolling(flow.flowId);
     } catch (error) {