fix(chat): isolate pending flows and cancel stale requests

src/lib/navigation/__tests__/subscription_exit.test.ts

@@ -39,6 +39,7 @@ describe("subscription exit helpers", () => {
   it("uses explicit chat image return urls first", async () => {
     consumePendingChatImageReturnMock.mockResolvedValue({
       reason: "image_paywall",
+      characterId: "character_elio",
       messageId: "msg_1",
       returnUrl: "/chat?image=msg_1",
       createdAt: 1,
@@ -73,12 +74,14 @@ describe("subscription exit helpers", () => {
   it("returns directly to private room without consuming chat state", async () => {
     consumePendingChatImageReturnMock.mockResolvedValue({
       reason: "image_paywall",
+      characterId: "character_elio",
       messageId: "msg_1",
       returnUrl: "/chat?image=msg_1",
       createdAt: 1,
     });
     peekPendingChatUnlockMock.mockResolvedValue({
       reason: "single_message_unlock",
+      characterId: "character_elio",
       displayMessageId: "msg_1",
       messageId: "msg_1",
       kind: "image",
@@ -101,6 +104,7 @@ describe("subscription exit helpers", () => {
   it("keeps private room ahead of stale chat state after payment", async () => {
     peekPendingChatUnlockMock.mockResolvedValue({
       reason: "single_message_unlock",
+      characterId: "character_elio",
       displayMessageId: "msg_1",
       messageId: "msg_1",
       kind: "image",
@@ -119,6 +123,7 @@ describe("subscription exit helpers", () => {
   it("keeps pending chat unlocks ahead of chat fallback after payment", async () => {
     peekPendingChatUnlockMock.mockResolvedValue({
       reason: "single_message_unlock",
+      characterId: "character_elio",
       displayMessageId: "msg_1",
       messageId: "msg_1",
       kind: "image",
@@ -136,6 +141,7 @@ describe("subscription exit helpers", () => {
   it("peeks chat unlock return urls without clearing them", async () => {
     peekPendingChatUnlockMock.mockResolvedValue({
       reason: "single_message_unlock",
+      characterId: "character_elio",
       displayMessageId: "msg_1",
       messageId: "msg_1",
       kind: "image",
@@ -154,6 +160,7 @@ describe("subscription exit helpers", () => {
     consumePendingChatImageReturnMock.mockResolvedValue(null);
     peekPendingChatUnlockMock.mockResolvedValue({
       reason: "single_message_unlock",
+      characterId: "character_elio",
       displayMessageId: "msg_1",
       messageId: "msg_1",
       kind: "image",