fix(web): preserve the visible chat window during rewind (#1766)

* fix(web): preserve chat window during rewind

* fix(web): scope rewind invalidation preservation

* fix(web): clear unknown rewind boundaries

* fix(web): deduplicate rewind invalidations

* fix(web): retain rewind dedupe history

shared/src/resume.test.ts

@@ -81,6 +81,18 @@ describe('resume schemas', () => {
         }).success).toBe(true)
     })
 
+    it('accepts rewind details on messages-invalidated events', () => {
+        expect(SyncEventSchema.parse({
+            type: 'messages-invalidated',
+            sessionId: 'session-1',
+            reason: 'rewind',
+            truncateFromLocalId: 'user-message-1'
+        })).toMatchObject({
+            reason: 'rewind',
+            truncateFromLocalId: 'user-message-1'
+        })
+    })
+
     it('validates structured session and machine update patches', () => {
         expect(SyncEventSchema.safeParse({
             type: 'session-updated',

shared/src/schemas.ts

@@ -558,7 +558,9 @@ export const SyncEventSchema = z.discriminatedUnion('type', [
         message: DecryptedMessageSchema
     }),
     SessionChangedSchema.extend({
-        type: z.literal('messages-invalidated')
+        type: z.literal('messages-invalidated'),
+        reason: z.literal('rewind').optional(),
+        truncateFromLocalId: z.string().min(1).optional()
     }),
     SessionChangedSchema.extend({
         type: z.literal('scheduled-matured')