bugfix: _energy_ratio bug fix (shape errors)

[artur-pa]

Which issue(s) are closed by this pull request?

Closes #132

Changes proposed in this pull request:

Fix shape mismatch and scalar index bug in _energy_ratio computation, used by #109 and #114

Problem
Two bugs in the EDC-based energy ratio calculation caused incorrect results or shape errors:

1. energy_decay_curve2_values was initialized with energy_decay_curve1.cshape + (2,)
   instead of energy_decay_curve2.cshape + (2,). When the two EDCs have different channel
   shapes, this produced an incorrectly sized array, leading to wrong assignments or a shape
   mismatch error.

2. The return value of find_nearest_time() was used directly as an index without wrapping
   it in np.atleast_1d(). When only a single infinite limit was present, find_nearest_time()
   returned a scalar, and the subsequent advanced indexing with [..., idx] collapsed a
   dimension unexpectedly, silently producing incorrect values in both
   energy_decay_curve1_values and energy_decay_curve2_values.

Fix

• Corrected the shape initialization of energy_decay_curve2_values to use
  energy_decay_curve2.cshape.
• Wrapped find_nearest_time() results in np.atleast_1d() for both the denominator and
  numerator index lookups to ensure consistent array indexing regardless of how many infinite
  limits are present.
• Add test

[Copilot]

Pull request overview

This PR fixes two bugs in the _energy_ratio function that caused shape mismatches and incorrect results when computing energy ratios from EDCs with different channel shapes or when using np.inf limits.

Changes:

• Fixed incorrect shape initialization for energy_decay_curve2_values to use energy_decay_curve2.cshape instead of energy_decay_curve1.cshape
• Added np.atleast_1d() wrapper around find_nearest_time() results to ensure consistent array indexing
• Added regression test and refactored test parametrization data into shared constant

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pyrato/parameters.py	Fixed shape initialization bug (line 330) and wrapped find_nearest_time() calls with np.atleast_1d() (lines 320-324, 332-336) to handle scalar returns correctly
tests/test_parameters.py	Added _MULTICHANNEL_ENERGY_SHAPES constant for shared test data, refactored existing test to use it, and added new regression test test_energy_ratio_inf_limit_multichannel_shape

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[f-brinkmann]

I noted that a few ruff errors are caused by this. Can you please fix them. The remaining errors are fixed by #134

[artur-pa]

I noted that a few ruff errors are caused by this. Can you please fix them. The remaining errors are fixed by #134

ruff tests have been completed!

[mberz]

Seems like the git history is erroneous. Please fix this before we proceed.