Validate parameter form inputs at entry-time instead of silently reverting

[pauladkisson]

Sub-issue of #138.

Many numeric fields in the input-parameters form are implemented as pn.widgets.LiteralInput(type=int, ...). When a user types a non-numeric value (e.g. "blah some text"), Panel silently reverts the field to the last valid value. This is visually confusing — users can't tell whether their input was accepted, and there's no feedback explaining why it was rejected.

The z-score baseline fields (baseline_wd_strt, baseline_wd_end) are one example, addressed in #283 by switching to pn.widgets.IntInput, which rejects non-numeric input at the browser level (native <input type="number">).

The same treatment should be applied to the other LiteralInput(type=int) widgets in src/guppy/frontend/input_parameters.py so the form behaves consistently:

• timeForLightsTurnOn
• numberOfCores
• moving_wd
• highAmpFilt
• transientsThresh
• moving_avg_filter
• no_channels_np
• nSecPrev, nSecPost
• timeInterval
• bin_psth_trials
• baselineCorrectionStart, baselineCorrectionEnd