fix(desktop): route host.warmProfile through the guarded prewarm resolver

apps/desktop/src/sdk/index.test.ts

@@ -1,10 +1,61 @@
-import { afterEach, describe, expect, it } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 
 import { createClientSessionState } from '@/lib/chat-runtime'
 import { host } from '@/sdk'
 import { setActiveSessionId, setAwaitingResponse, setBusy } from '@/store/session'
 import { clearAllSessionStates, publishSessionState } from '@/store/session-states'
 
+// The warm path must route through the guarded prewarm resolver, not dial the
+// gateway directly: gateway.ts's openSecondaryCount and pool-limits' cap atom
+// are the two signals prewarmProfileBackend consults, so mocking them lets the
+// tests observe the guard's decision through the ONLY side effect that matters
+// — whether openGatewayForProfile was dialed.
+const warmMocks = vi.hoisted(() => ({
+  openGatewayForProfile: vi.fn(async (_profile: string) => undefined),
+  openSecondaryCount: vi.fn(() => 0)
+}))
+
+vi.mock('@/store/gateway', async importOriginal => ({
+  ...((await importOriginal()) as Record<string, unknown>),
+  openGatewayForProfile: warmMocks.openGatewayForProfile,
+  openSecondaryCount: warmMocks.openSecondaryCount
+}))
+
+vi.mock('@/store/pool-limits', async () => {
+  const { atom } = await import('nanostores')
+
+  return { $poolLimits: atom({ idleMs: 600_000, maxBackends: 3 }) }
+})
+
+describe('host.warmProfile pool-saturation contract', () => {
+  beforeEach(() => {
+    warmMocks.openGatewayForProfile.mockClear()
+    warmMocks.openSecondaryCount.mockReturnValue(0)
+  })
+
+  it('dials through the guarded path when a pool slot is free', () => {
+    warmMocks.openSecondaryCount.mockReturnValue(2)
+
+    host.warmProfile('warm-free-slot')
+
+    expect(warmMocks.openGatewayForProfile).toHaveBeenCalledWith('warm-free-slot')
+  })
+
+  it('skips the speculative spawn when every pool slot is occupied', () => {
+    warmMocks.openSecondaryCount.mockReturnValue(3)
+
+    host.warmProfile('warm-saturated')
+
+    expect(warmMocks.openGatewayForProfile).not.toHaveBeenCalled()
+  })
+
+  it('ignores blank profile names', () => {
+    host.warmProfile('   ')
+
+    expect(warmMocks.openGatewayForProfile).not.toHaveBeenCalled()
+  })
+})
+
 describe('host.state turn flags', () => {
   afterEach(() => {
     setActiveSessionId(null)

apps/desktop/src/sdk/index.ts

@@ -65,6 +65,7 @@ import {
   newSessionInAgent,
   newSessionInProfile,
   normalizeProfileKey,
+  prewarmProfileBackend,
   refreshProfiles,
   selectProfile,
   setActiveProfile,
@@ -643,20 +644,25 @@ export const host = {
   },
 
   /** Pre-dial a profile's gateway socket in the background — pool-only, no
-   *  activation, no navigation, no scope change (openGatewayForProfile; it
-   *  already no-ops for shared-remote routes and the primary). Roster UIs
-   *  call this after mount so the FIRST click on an agent doesn't pay the
-   *  whole backend spawn + socket dial latency. Fire-and-forget: failures
-   *  are swallowed — the click path re-runs its own ensure and surfaces
-   *  errors properly. */
+   *  activation, no navigation, no scope change. Delegates to
+   *  prewarmProfileBackend so plugin surfaces get the SAME pool-saturation
+   *  guard, hover dwell, and per-profile throttle as the built-in rail
+   *  (#91545): a pointer sweep across a plugin roster (bot-row's
+   *  onPointerEnter fires with no dwell of its own) previously spawned at
+   *  pointer speed, filled the local backend pool past maxBackends, and left
+   *  the next profile's spawn queued until the 30s slot timeout — observed
+   *  as a profile surface that hangs forever while every other profile
+   *  renders. It already no-ops for shared-remote routes and the primary.
+   *  Fire-and-forget: failures are swallowed — the click path re-runs its
+   *  own ensure and surfaces errors properly. */
   warmProfile: (profile: string): void => {
     const name = (profile ?? '').trim()
 
-    if (!name || name === $activeGatewayProfile.get()) {
+    if (!name) {
       return
     }
 
-    void openGatewayForProfile(name).catch(() => undefined)
+    prewarmProfileBackend(name)
   },
 
   /** Delete a profile THROUGH the desktop's teardown-routed REST path — the