chore: enforce figma links in relevant prs

[ovitrif]

Closes #1234

This PR adds a Design section to the pull request workflow so applicable UI changes reference their Figma frames and all other changes use an explicit N/A case.

Description

• Adds the Design section to the pull request template.
• Applies the same screens-map, N/A, uncertainty, and advisory-review policy to agent instructions and /pr generation.

Design

N/A — no UI changes.

Preview

N/A — no user-visible changes.

QA Notes

Manual Tests

N/A

Automated Checks

• Local verification: git diff --check origin/master...HEAD; inspected policy coverage for UI changes with existing designs, UI changes without designs, non-UI changes, missing or uncertain map entries, and omitted applicable links.

[greptile-apps]

Confidence Score: 5/5

The documentation-only policy changes appear safe to merge.

Summary

• Directs UI changes with existing designs to relevant Figma frames, starting from the screen map.
• Defines explicit N/A cases for changes without designs or user-visible UI.
• Keeps missing design links advisory and non-blocking.