fix(ipc): register credentials + oauth handlers in main runtime

The `registerCredentialIpcHandlers` and `registerOAuthIpcHandlers`
entry points existed in `ipc-credentials-handlers.ts` and
`ipc-oauth-handlers.ts` but were never called — `registerHandlers()`
in `main-runtime-support.ts` only wired `registerCoreHandlers` and
`registerDomainHandlers`. The result: every renderer call to
`credentials:list` / `credentials:save` / `credentials:remove` /
`credentials:test` / `oauth:start` / `oauth:cancel` /
`oauth:prompt-response` / `oauth:manual-code-response` crashed
with "No handler registered".

Wire both handler families against the PiRuntimeServices container
(credentialStore, credentialResolver, oauthLoginService) already
exposed via `serviceGraph.getPiRuntime()`. The refreshConnectorHealth
callback reuses the existing connectorHealthService so status
badges flip between `ready` and `auth_required` immediately after
a save/login.

typecheck 0 / lint 0-0 / build 0-0 / test:unit 508/508 preserved.

src/main/main-runtime-support.ts

@@ -9,6 +9,9 @@ import type { AppDatabase } from "./database";
 import { seedDefaultAutomationRules as seedDefaultAutomationRulesImpl } from "./default-automation-rules";
 import { registerCoreHandlers } from "./ipc-core-handlers";
 import { registerDomainHandlers } from "./ipc-domain-handlers";
+import { registerCredentialIpcHandlers } from "./ipc-credentials-handlers";
+import { registerOAuthIpcHandlers } from "./ipc-oauth-handlers";
+import { fail } from "./ipc-core-common";
 import type { ThreadIntegrationService } from "./thread-integration";
 
 type BootstrapResult = Awaited<ReturnType<typeof bootstrapApplication>>;
@@ -187,6 +190,30 @@ export function createMainRuntimeSupport(state: MainRuntimeState) {
         publishDomainChanged();
       },
     });
+
+    const piRuntime = requireServiceGraph().getPiRuntime();
+    if (!piRuntime) {
+      throw new Error("Pi-mono runtime services are not initialized.");
+    }
+
+    registerCredentialIpcHandlers({
+      store: piRuntime.credentialStore,
+      resolver: piRuntime.credentialResolver,
+      registerHandle: requireIpcSupport().registerHandle,
+      emitEvent,
+      refreshConnectorHealth: async (connectorId) => {
+        await requireConnectorHealthService().checkConnector(connectorId as ConnectorId);
+      },
+      fail,
+      logger: log,
+    });
+
+    registerOAuthIpcHandlers({
+      service: piRuntime.oauthLoginService,
+      registerHandle: requireIpcSupport().registerHandle,
+      fail,
+      logger: log,
+    });
   }
 
   return {