[djhoese]

This is on top of #108. Claude identified various bugs in the code or things that were not yet implemented. Claude wrote most of the code here with review and suggestions from me. Each commit after the ones in #108 are deliberately separate for each issue that Claude identified. All the issues are edge cases where we're very unlikely to run into these things in our main use cases (i.e. satpy). Here is my summary:

1. If a fill character is the same as a type letter. So if someone formatted a string and wanted it shifted over 12 characters and to fill any empty space with a "d". That "d" is also the format type for integer and trollsift didn't handle that properly...but how often are people using d/x/f/etc as fill characters?
2. Fix parsing of values with 0s on the left. See test cases.
3. If someone used %% in a date format it was sometimes mishandled. Like %Y%%m%d. That %% should be turned into a single % as per the strftime/datetime spec, but trollsift would match the %m instead. The result is a difference between "2026%m08" (correct) versus "2026%0908". Again, who does this? But it was wrong. This was also the most annoying as far as how much code change had to happen for such a simple fix.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.47%. Comparing base (15a65f4) to head (3cabb01).
⚠️ Report is 27 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #110      +/-   ##
==========================================
+ Coverage   95.92%   96.47%   +0.54%     
==========================================
  Files           5        5              
  Lines         614      652      +38     
==========================================
+ Hits          589      629      +40     
+ Misses         25       23       -2     

Flag	Coverage Δ
unittests	96.47% <100.00%> (+0.54%)	⬆️

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[pnuu]

LGTM