Method refresh

src/main/lib/credential-manager.ts:595–623

* Refresh token for a source * * Returns the new access token, or null if refresh fails. * On success, credentials are automatically updated.

(source: LoadedSource)

   * On success, credentials are automatically updated.
   */
  async refresh(source: LoadedSource): Promise<string | null> {
    const cred = await this.load(source);
    if (!cred?.refreshToken) {
      debug(`[SourceCredentialManager] No refresh token for ${source.config.slug}`);
      return null;
    }

    // Google API refresh
    if (source.config.provider === 'google') {
      return this.refreshGoogle(source, cred);
    }

    // Slack API refresh
    if (source.config.provider === 'slack') {
      return this.refreshSlack(source, cred);
    }

    // Microsoft API refresh
    if (source.config.provider === 'microsoft') {
      return this.refreshMicrosoft(source, cred);
    }

    // MCP refresh
    if (source.config.type === 'mcp' && source.config.mcp?.url) {
      return this.refreshMcp(source, cred);
    }

    return null;
  }

  /**
   * Refresh Google OAuth token