fix(session-query): make persisted observation non-mutating

packages/session-persistence/session-persistence/tests/contract.ts

@@ -99,6 +99,15 @@ export function runPersistenceContract(name: string, make: () => Promise<Contrac
         const beforeRepair = (await persistence.listSnapshots())
           .find(snapshot => snapshot.header.id === m.id)?.revision
 
+        const inspected = await persistence.inspect(m.id)
+        const afterInspect = (await persistence.listSnapshots())
+          .find(snapshot => snapshot.header.id === m.id)?.revision
+        expect(afterInspect).toBe(beforeRepair)
+        expect(inspected.events.map(e => e.type)).toEqual([
+          'turn/start', 'user/message', 'step/start', 'assistant/message', 'step/end', 'turn/end',
+          'turn/start', 'step/start',
+        ])
+
         // load PRESERVES the interrupted turn's events (a turn can be huge — they
         // must not be truncated) and closes the orphaned turn with synthetic
         // boundary events: step/end (the step was open) then turn/end {interrupted}.

packages/session-persistence/session-persistence/tests/coordinator-contract.ts

@@ -643,11 +643,12 @@ export function runCoordinatorContract(name: string, makeFixture: () => Promise<
       }
     })
 
-    it('load rejects a missing session', async () => {
+    it('load and inspect reject a missing session', async () => {
       const fix = await makeFixture()
       const { ctx, fiber } = await freshCtx(fix)
       try {
         await expect(ctx.sessionPersistence.load(SessionId('nope'))).rejects.toThrow(/not found/)
+        await expect(ctx.sessionPersistence.inspect(SessionId('nope'))).rejects.toThrow(/not found/)
       } finally {
         await fiber.dispose()
         await fix.cleanup()

packages/session-persistence/session-persistence/tests/persistence.spec.ts

@@ -96,6 +96,10 @@ class MemoryPersistence extends SessionPersistence implements PersistenceBackend
     return this.coordinator.load(id)
   }
 
+  inspect(id: SessionId): Promise<{ meta: SessionHeader; events: SessionEvent[] }> {
+    return this.coordinator.inspect(id)
+  }
+
   // --- PersistenceBackend hooks (the Map storage primitives) ---
 
   // A Map-backed store has no torn tails, so `tornMarker` is never set.