Add links to image diff grid rows

[forsyth2]

Summary

Objectives:

• Automate process to go from high-level overview of testing diffs to high-resolution singular images. That is, provide a simple link.

Issue resolution:

• Closes [Feature]: Testing -- Add links to titles of each row of the image diff grid #766

Select one: This pull request is...

• a bug fix: increment the patch version
• a small improvement: increment the minor version
• a new feature: increment the minor version
• an incompatible (non-backwards compatible) API change: increment the major version

Small Change

• To merge, I will use "Squash and merge". That is, this change should be a single commit.
• Logic: I have visually inspected the entire pull request myself.
• Pre-commit checks: All the pre-commits checks have passed.

[forsyth2]

Will test this PR on the next few zppy test runs, e.g., for E3SM-Project/e3sm_diags#1021 & #760

[forsyth2]

Example is from E3SM-Project/e3sm_diags#1021 (comment)

[forsyth2]

I have used this commit to test both E3SM-Project/e3sm_diags#1021, the 2025-12-16 weekly test, #765. It works as intended; merging.