fix: restart idle sidecar on capability refresh

Force-refreshing sidecar capabilities now disposes the idle sidecar process before re-querying capabilities, so Kopaya can pick up backend sidecar changes and refreshed Copilot connection state without a full app restart.

Add a small helper and regression tests for the refresh decision.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/KopayaAppService.ts

@@ -496,7 +496,12 @@ export class KopayaAppService extends EventEmitter<AppServiceEvents> {
   }
 
   private async loadSidecarCapabilities(forceRefresh = false): Promise<SidecarCapabilities> {
-    if (forceRefresh || !this.sidecarCapabilities) {
+    if (forceRefresh) {
+      this.sidecarCapabilities = await this.sidecar.refreshCapabilities();
+      return this.sidecarCapabilities;
+    }
+
+    if (!this.sidecarCapabilities) {
       this.sidecarCapabilities = await this.sidecar.describeCapabilities();
     }
 

src/main/sidecar/sidecarProcess.ts

@@ -12,6 +12,7 @@ import type {
 } from '@shared/contracts/sidecar';
 import type { ChatMessageRecord } from '@shared/domain/session';
 import { createSidecarEnvironment } from '@main/sidecar/sidecarEnvironment';
+import { shouldRestartSidecarOnCapabilityRefresh } from '@main/sidecar/sidecarRefresh';
 import {
   markRunTurnPendingErrored,
   shouldHandleRunTurnEvent,
@@ -46,6 +47,14 @@ export class SidecarClient {
     return command;
   }
 
+  async refreshCapabilities(): Promise<SidecarCapabilities> {
+    if (shouldRestartSidecarOnCapabilityRefresh(this.hasActiveRunTurn())) {
+      await this.dispose();
+    }
+
+    return this.describeCapabilities();
+  }
+
   async validatePattern(pattern: ValidatePatternCommand['pattern']): Promise<unknown> {
     return this.dispatch<unknown>({
       type: 'validate-pattern',
@@ -71,6 +80,16 @@ export class SidecarClient {
     this.process = undefined;
   }
 
+  hasActiveRunTurn(): boolean {
+    for (const pending of this.pending.values()) {
+      if (pending.kind === 'run-turn') {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
   private async ensureProcess(): Promise<ChildProcessWithoutNullStreams> {
     if (this.process && !this.process.killed) {
       return this.process;

src/main/sidecar/sidecarRefresh.ts

@@ -0,0 +1,3 @@
+export function shouldRestartSidecarOnCapabilityRefresh(hasActiveRunTurn: boolean): boolean {
+  return !hasActiveRunTurn;
+}

tests/main/sidecarRefresh.test.ts

@@ -0,0 +1,13 @@
+import { describe, expect, test } from 'bun:test';
+
+import { shouldRestartSidecarOnCapabilityRefresh } from '@main/sidecar/sidecarRefresh';
+
+describe('shouldRestartSidecarOnCapabilityRefresh', () => {
+  test('restarts the sidecar when no run-turn is active', () => {
+    expect(shouldRestartSidecarOnCapabilityRefresh(false)).toBe(true);
+  });
+
+  test('keeps the existing sidecar when a run-turn is active', () => {
+    expect(shouldRestartSidecarOnCapabilityRefresh(true)).toBe(false);
+  });
+});