Added cumulative XUV Flux and reproduction of the "Cosmic Shoreline"

[RoryBarnes]

Proposed changes

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[github-actions]

Test Results

19 599 tests   19 599 ✅  1m 38s ⏱️
     1 suites       0 💤
     1 files         0 ❌

Results for commit d02a6d7.

♻️ This comment has been updated with latest results.