chore: remove Cursor workflows replaced by Multica agent team

[shivchander]

Background

We now have a Multica agent team (sdg-lead, sdg-builder, sdg-evaluator) handling code review, CI fixes, and doc updates. The 3 Cursor workflows are redundant.

What to do

Remove these 3 files:

• .github/workflows/cursor-code-review.yml — replaced by sdg-evaluator's full GitHub code reviews
• .github/workflows/cursor-fix-ci.yml — replaced by sdg-builder iterating on CI failures through the review loop
• .github/workflows/cursor-update-docs.yml — replaced by doc gardening Autopilot + sdg-builder

Acceptance criteria

• All 3 cursor workflow files deleted
• No other workflows reference them
• CI still passes

[shivchander]

PR: #788