v1.1.5: spectrogram fix and folder settings

[1.1.5] — 2026-09-09

Added

• Folder names can be built from parts, like file names. Subfolder →
  From parts … offers calendar week, week span (07.09-13.09), date, year,
  month, day and free text, tickable and reorderable, joined with spaces —
  folders may hold those, file names here may not. KW37 07.09-13.09 Voice Training is what the default selection plus a word of your own produces,
  which is how such folders usually get made by hand. The fixed periods stay
  where they were; picking one changes nothing about how it behaves.
• A Day name part. With Month now contributing only the month, year,
  month and day can be ticked separately and add up to what Date gives in
  one piece.

Fixed

• The detail spectrogram stays sharp when you zoom in. It was computed
  once at the width of the chart, so zooming stretched a handful of columns
  into blocks. Both charts are now redrawn for whatever stretch of time is on
  screen. The spectrogram gets the same number of columns over less time, and
  its analysis window shrinks with the view — 1024 samples is 64 ms at 16 kHz,
  so at a 25 ms zoom every column used to see almost the same piece of audio
  and the picture turned into horizontal streaks. Below roughly a tenth of a
  second you now see the individual glottal pulses. The trade is frequency
  resolution, which is exactly the trade you want when zooming in. Brightness
  is still derived from the whole recording, so a quiet passage does not
  brighten up just because you looked at it closely. The image also sits where
  it belongs now: the first column starts half a window in, and that offset
  used to be ignored.
• The waveform above it is redrawn from the samples themselves. Its
  envelope had 2400 points for the whole recording — one every 2.5 ms in a
  six-second take, which at high zoom left a staircase with no relation to the
  signal. A narrow view now plots one point per sample.
• The spectrogram comes back at the height it left. Both charts in the
  advanced area now have fixed stretch factors; without them Qt redistributed
  the space by size hints and the chart returned smaller or larger than
  before.