Allow predict_tile to return predictions in original geo-coordinates

[ethanwhite]

Replaces #1250 with the improvements I suggested there along with some additional performance improvements (i.e., don't open files twice).

Closes #608

AI-Assisted Development

• I used AI tools (e.g., GitHub Copilot, ChatGPT, etc.) in developing this PR
• I understand all the code I'm submitting
• I have reviewed and validated all AI-generated code

AI tools used (if applicable):
Claude Code used for initial test creation. I reviewed the resulting tests.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.74%. Comparing base (2b26da4) to head (bc7ef2e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1423      +/-   ##
==========================================
+ Coverage   86.67%   86.74%   +0.06%     
==========================================
  Files          28       28              
  Lines        4069     4075       +6     
==========================================
+ Hits         3527     3535       +8     
+ Misses        542      540       -2     

Flag	Coverage Δ
unittests	86.74% <100.00%> (+0.06%)	⬆️

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[henrykironde]

Thanks @musaqlain @ethanwhite and @Keenan-Nicholson for the contribution.