Guard shared AI Vault inflight cleanup against concurrent key replacement

The extracted cache module's .finally() cleared inflight tracking
unconditionally, dropping the if (inflightKey === key) guard its sibling
outer cache kept: an older scan resolving after a different-key scan
replaced the tracking would null the newer scan's dedup slot, so a
re-request started a duplicate transcript rescan. Mirrors the sibling
guard; the regression test flushes a macrotask so a reverted guard fails
fast on the call count instead of hanging.

Co-authored-by: Orca <help@stably.ai>

src/main/ai-vault/cached-session-list.ts

@@ -70,8 +70,12 @@ export async function listAiVaultSessions(args?: AiVaultListArgs): Promise<AiVau
       return result
     })
     .finally(() => {
-      inflightKey = null
-      inflightList = null
+      // Only clear tracking if it still refers to this request: a concurrent
+      // different-key scan may have replaced it and must stay dedupable.
+      if (inflightKey === key) {
+        inflightKey = null
+        inflightList = null
+      }
     })
   return inflightList
 }

src/main/runtime/rpc/methods/ai-vault.test.ts

@@ -129,6 +129,33 @@ describe('aiVault.listSessions handler + shared cache', () => {
     expect(scanAiVaultSessions).toHaveBeenCalledTimes(1)
   })
 
+  it('keeps a newer different-key scan dedupable after an older scan resolves', async () => {
+    // Why: the resolving scan's cleanup must not clear tracking a concurrent
+    // different-key scan replaced, or re-requests start a duplicate rescan.
+    const deferreds: ((result: AiVaultListResult) => void)[] = []
+    scanAiVaultSessions.mockImplementation(
+      () => new Promise<AiVaultListResult>((resolve) => deferreds.push(resolve))
+    )
+    // The scanner is invoked a microtask after the call (WSL-home await), so
+    // wait for each deferred to register before driving resolution order.
+    const scanA = listAiVaultSessions({ limit: 100 })
+    await vi.waitFor(() => expect(deferreds).toHaveLength(1))
+    const scanB = listAiVaultSessions({ limit: 200 })
+    await vi.waitFor(() => expect(deferreds).toHaveLength(2))
+    deferreds[0]?.(makeResult())
+    await scanA
+    // Re-request key B while its first scan is still pending: must dedupe.
+    const scanBAgain = listAiVaultSessions({ limit: 200 })
+    // Flush a macrotask so that a wrongly-started duplicate scan would reach the
+    // mock (it fires a microtask after the WSL-home await): guarded stays 2, a
+    // reverted guard reads 3, so this assertion — not a Promise.all hang — pins
+    // the fix.
+    await new Promise((resolve) => setTimeout(resolve))
+    expect(scanAiVaultSessions).toHaveBeenCalledTimes(2)
+    deferreds[1]?.(makeResult())
+    await Promise.all([scanB, scanBAgain])
+  })
+
   it('restamps the shared cached result as the addressed runtime host', async () => {
     scanAiVaultSessions.mockResolvedValue({
       sessions: [makeSession()],