Verify infer_freq() already used for non-daily input validation

[Copilot]

Description

Issue #112 requested SRRAnalysis.__init__() use pd.infer_freq() to validate truly daily data instead of rejecting series without explicit frequency attributes.

Investigation confirms this is already implemented. Current code at lines 69-80 of soiling.py:

if pd.infer_freq(self.pm.index) != 'D':
    raise ValueError('Daily performance metric series must have daily frequency')

pd.infer_freq() returns 'D' for daily data even when .freq=None, allowing implicit daily series to proceed while rejecting truly non-daily data.

Verified by:

• Existing test test_soiling_srr_non_daily_inputs validates implicit daily series pass
• All 35 soiling tests pass
• Manual testing confirms correct behavior for explicit freq, implicit freq, and non-daily cases

No code changes required.

Checklist

• Code changes are covered by tests
• Code changes have been evaluated for compatibility/integration with TrendAnalysis
• New functions added to __init__.py
• API.rst is up to date, along with other sphinx docs pages
• Example notebooks are rerun and differences in results scrutinized
• Updated changelog

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Consider warning for non-daily inputs to srr_analysis.init()</issue_title>
<issue_description>@GregoryKimball raised the question in PR #112 whether soiling.srr_analysis.__init__() should raise warnings instead of the current behavior to raise aValueError when called with Pandas series that don't have the frequency set.

(At time of entry, this issue does not apply to master) </issue_description>

<agent_instructions>has this issue been addressed since it was raised?</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@mdeceglie Let's use `infer_freq()` to check wether it is truly daily and allow the code to proceed

• Fixes Consider warning for non-daily inputs to srr_analysis.__init__() #113

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.19%. Comparing base (e107469) to head (c4ce7d0).

Additional details and impacted files

@@                          Coverage Diff                           @@
##           fix-numpy-and-pandas-compatibility     #477      +/-   ##
======================================================================
+ Coverage                               96.10%   96.19%   +0.08%     
======================================================================
  Files                                      12       12              
  Lines                                    2287     2287              
======================================================================
+ Hits                                     2198     2200       +2     
+ Misses                                     89       87       -2     

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