feat: modpacks

[Vilsol]

---

Rob's list of assorted Rose To-Do's before this can be merged:

• Make real name for 20260321003544 migration
• Review all added code comments to ensure they are still relevant. If they suggest future work/changes, ideally turn them into github issues with links to that line in the code so we can discuss them later

[codecov]

Codecov Report

❌ Patch coverage is 59.64912% with 23 lines in your changes missing coverage. Please review.
✅ Project coverage is 43.59%. Comparing base (7b96fac) to head (c87e8ae).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
dataloader/loaders.go	0.00%	14 Missing ⚠️
db/modpack.go	76.92%	5 Missing and 4 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           staging     #125      +/-   ##
===========================================
+ Coverage    41.73%   43.59%   +1.85%     
===========================================
  Files          128      113      -15     
  Lines         6146     6375     +229     
===========================================
+ Hits          2565     2779     +214     
+ Misses        3191     3149      -42     
- Partials       390      447      +57     

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