docs(customer-portal-sso): require portal slug prefix in redirect_to

[vtsl-DevRev]

Summary

Updates the JWT SSO example README to clarify that the redirect_to query param must always begin with the portal slug (//...); values without the slug prefix are rejected and the user is sent to the default landing page. Refreshes the example URL in step 6 to match the new convention.

Connected Issues

• Work Item :- https://app.devrev.ai/devrev/issue/PORT-82

Craftsmanship, Integrity, and Devil’s Advocacy

• Testing: Negative test cases: null or default values, crash and fault injection tests
• Testing: Boundary conditions: rolling upgrades, denial-of-service, etc.
• Testing: Fixing a few existing — flaky or permanently-broken — test cases
• Observing: Detailed error codes so machines can understand
• Observing: Adding superior metrics for future debugging
• Observing: Tracing the hairiest pathways for field serviceability
• Training: KnowledgeOps update? So AI always works.