Degradation timeseries plot - add left or right label option

[cdeline]

This enhancement fixes #455. Adds an input parameter 'label' to have the degradation timeseries plot either right-labeled (current default) or center or left-labeled. This is the first PR of three that is required to enable multi-Year-on-Year degradation analysis and plotting.

• 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

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.33%. Comparing base (416778c) to head (8451499).

Additional details and impacted files

@@               Coverage Diff               @@
##           development     #456      +/-   ##
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+ Coverage        96.26%   96.33%   +0.06%     
===============================================
  Files               12       12              
  Lines             2276     2290      +14     
===============================================
+ Hits              2191     2206      +15     
+ Misses              85       84       -1     

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[cdeline]

Outcome of our 6/17/25 PV Fleet meeting to review this PR: Yes, it seems that the default behavior is not ideal, given the 2-year gap from timeseries data start to time-dependent degradation rate. Best approach would be to use a timestamp in the center of the YoY slope, and use a window centered on the datapoint. If necessary, pad the dataframe with NaN's to account for the beginning of the time series that might not have enough points in the window. Possible other functions to investigate: scipy.ndimage.median_filter or np.convolve

[Copilot]

Pull Request Overview

This enhancement adds a label parameter to the degradation_timeseries_plot function, allowing users to control how the time series data is labeled on the plot. The change enables left, center, or right labeling options instead of only the previous default right labeling behavior.

• Adds label parameter with 'right', 'center', and 'left' options to control plot labeling
• Updates documentation and changelog to reflect the new functionality
• Adds comprehensive test coverage for the new parameter options

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
rdtools/plotting.py	Implements the new label parameter with validation and offset calculations for different labeling positions
rdtools/test/plotting_test.py	Adds test cases covering all label options and error conditions
docs/sphinx/source/changelog/pending.rst	Documents the enhancement in the pending changelog
docs/sphinx/source/changelog.rst	Includes the pending changelog in the main changelog
docs/sphinx/source/changelog/v3.0.1.rst	Adds version 3.0.1 changelog entry
docs/notebook_requirements.txt	Updates dependency versions (Jinja2, tornado, notebook)

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