refactor: prune dead IPC surface and orphaned modules

Drop code that nothing consumed. Verified by full renderer+shared grep:
every removed channel had zero callers via window.agentCompany.* and
zero references from desktop-api types. No backend internal use either —
the database/API-server layers keep their methods, only the IPC exposure
goes.

Removed IPC handlers (26 total):

  Thread CRUD surface (12) — writes happen inside the backend
    createThread, listThreads, addThreadEvent,
    setThreadWaitState, resolveThreadWaitState,
    addParticipant, removeParticipant, listParticipants,
    subscribeThread, unsubscribeThread,
    listSubscriptions, listSubscribedThreads
    (kept reads: getThread, listThreadEvents, listThreadWaitStates)

  Half-implemented features (13)
    saveSecret, listComments, getAgentMetrics, getApiPort,
    listWakeupRequests, listAgentMessages, autoAssignTask,
    listRunEvents, recoveryDismiss,
    getHeartbeatPolicy, setHeartbeatPolicy,
    getRuntimeState, setRuntimeState

  Whole vertical slice: openConnectorAuthTerminal
    IPC handler + channel + preload + DesktopApi type +
    connector-auth-service function + useConnectorCallbacks
    handleLoginConnector + OnboardingContext.onLoginConnector +
    OnboardingWizard wiring. Pi-mono has no CLI auth flow;
    the no-op that "returned false for legacy UI compatibility"
    had no legacy UI left.

Orphaned modules (zero importers in repo):
  src/main/runtime-env.ts
  src/main/database-stale-recovery.ts

Dead schema files (only referenced by their own barrel re-export):
  schemas-participants, schemas-subscriptions, schemas-heartbeat,
  schemas-run-events, schemas-runtime-state, schemas-wakeup

Renderer leftovers:
  .activity-row-enter CSS + its two unreferenced keyframes
  5 orphan i18n keys (app.console, app.refresh, app.expand,
  activity.timeline, auto.trigger) left over from earlier feature
  deletions

Also update two unit tests that mocked openConnectorAuthTerminal in
the RegisterCoreHandlersDependencies pick.

src/renderer/components/company-onboarding/OnboardingContext.tsx

@@ -59,7 +59,6 @@ export interface OnboardingConnectorsContextValue {
     model: string | null,
     notes?: string,
   ) => void;
-  onLoginConnector: (connectorId: string) => void;
 
   selectedConnectorId: ConnectorId | "";
   setSelectedConnectorId: (value: ConnectorId | "") => void;

src/renderer/components/company-onboarding/OnboardingWizard.tsx

@@ -83,7 +83,7 @@ export function CompanyOnboarding({
     }
   }, [step, nodeStatus, checkNode]);
 
-  const { handleTestConnector, handleSaveConnector, handleLoginConnector, handleInstallCommand } =
+  const { handleTestConnector, handleSaveConnector, handleInstallCommand } =
     useConnectorCallbacks(connectors);
 
   const {
@@ -208,7 +208,6 @@ export function CompanyOnboarding({
       hasAtLeastOneReady,
       onTestConnector: (id) => void handleTestConnector(id),
       onSaveConnector: (id, env, model, notes) => void handleSaveConnector(id, env, model, notes),
-      onLoginConnector: (id) => void handleLoginConnector(id),
       selectedConnectorId,
       setSelectedConnectorId,
       selectedModel,
@@ -228,7 +227,6 @@ export function CompanyOnboarding({
       hasAtLeastOneReady,
       handleTestConnector,
       handleSaveConnector,
-      handleLoginConnector,
       selectedConnectorId,
       setSelectedConnectorId,
       selectedModel,

src/renderer/components/company-onboarding/useConnectorCallbacks.ts

@@ -36,30 +36,6 @@ export function useConnectorCallbacks(connectors: ProfileSnapshot["connectors"])
     }
   }, [connectors]);
 
-  const handleLoginConnector = useCallback(async (connectorId: string) => {
-    try {
-      unwrap(await window.agentCompany.openConnectorAuthTerminal(connectorId as ConnectorId));
-    } catch (error) {
-      console.warn(
-        `[onboarding/useConnectorCallbacks] openConnectorAuthTerminal(${connectorId}) failed: ${error instanceof Error ? error.message : String(error)}`,
-      );
-      return;
-    }
-    // Poll connector health after login terminal opens (same pattern as ConnectorEditor)
-    let attempts = 0;
-    const poll = setInterval(async () => {
-      attempts++;
-      if (attempts > 12) { clearInterval(poll); return; }
-      try {
-        unwrap(await window.agentCompany.testConnector(connectorId as ConnectorId));
-      } catch (error) {
-        console.warn(
-          `[onboarding/useConnectorCallbacks] post-login testConnector(${connectorId}) failed (attempt ${attempts}): ${error instanceof Error ? error.message : String(error)}`,
-        );
-      }
-    }, 5000);
-  }, []);
-
   const handleInstallCommand = useCallback(async (commandKey: z.infer<typeof openTerminalCommandSchema>["commandKey"]) => {
     try {
       unwrap(await window.agentCompany.openTerminalCommand({ commandKey }));
@@ -88,5 +64,5 @@ export function useConnectorCallbacks(connectors: ProfileSnapshot["connectors"])
     }, 5000);
   }, [connectors]);
 
-  return { handleTestConnector, handleSaveConnector, handleLoginConnector, handleInstallCommand };
+  return { handleTestConnector, handleSaveConnector, handleInstallCommand };
 }