Architecture Cleanup: Remove or Replace Dead Tutorials Navigation

[JMG3000]

Jira Tracking

• Jira Site: https://jmg-github-revamp.atlassian.net
• Jira Project: PIMP
• Jira Issue Type: Task
• Jira Key: PIMP-7
• Jira Priority: Highest
• Jira URL: https://jmg-github-revamp.atlassian.net/browse/PIMP-7

Objective

Remove the broken /tutorials nav target or implement the route.

Scope

• Update header nav in components/Layout.tsx
• If keeping Tutorials, add src/pages/tutorials.tsx

Acceptance Criteria

• Clicking all header nav links does not produce unexpected 404s
• Navigation labels and destinations are intentional and current