01-tutorials - Add inbound auth code flow with Okta tutorial for AgentCore Gateway

[dsuarezsoutoaws]

Which component is impacted by this improvement?

• 01-AgentCore-runtime
• 02-AgentCore-gateway
• 03-AgentCore-identity
• 04-AgentCore-memory
• 05-AgentCore-tools
• 06-AgentCore-observability
• 07-AgentCore-E2E

Improvement Description
Add a new tutorial (17-inbound-auth-code-flow-okta) with a Jupyter notebook that walks
through setting up OAuth 2.0 Authorization Code Flow with PKCE on AgentCore Gateway
using Okta as the identity provider. Covers creating an Okta SPA app, creating a Gateway
with CUSTOM_JWT auth, installing mcp-remote as an OAuth proxy, and configuring Kiro IDE's
mcp.json. Includes 9 annotated screenshots.