feat: Tema sonoro Voyager per KDE Plasma

- index.theme con Directories=stereo, OutputProfile=stereo,
  Inherits=freedesktop ed Example=theme-demo
- 61 cue sintetizzati da zero (Ogg Vorbis 48 kHz stereo) piu' il montaggio
  di anteprima theme-demo.oga
- tools/gen_sounds.py: motore di sintesi riproducibile (radio a banda stretta
  con AM a onda quadra, quantizzazione a 7 bit, beep di telemetria, sweep)
- tools/verify_theme.py: verifica della spec, igiene audio (clipping, DC,
  click ai bordi) e copertura dei nomi suono richiesti dai notifyrc di KDE
- preview/index.html: player nel browser per ogni cue del tema
- Makefile, install.sh, LICENSES (audio CC-BY-SA-4.0, codice BSD-2-Clause)

CHANGELOG.md

@@ -0,0 +1,29 @@
+# Changelog
+
+All notable changes to this project are documented here.
+The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/);
+versioning follows [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [1.0.0] - 2026-09-20
+
+### Added
+
+* Initial release: 61 cues plus a `theme-demo` preview montage, all
+  synthesised from scratch and encoded as 48 kHz stereo Ogg Vorbis.
+* `index.theme` declaring `Directories=stereo`, `OutputProfile=stereo`,
+  `Inherits=freedesktop` and `Example=theme-demo`.
+* `tools/gen_sounds.py` — the complete synthesis engine (FM voices, Karplus-Strong
+  plucks, swept band-passed noise, sub impacts, additive pads, synthetic
+  convolution reverb, degradation modelling).
+* `tools/verify_theme.py` — validates the theme against the freedesktop spec and
+  reports coverage of the sound names requested by the installed KDE
+  `*.notifyrc` files.
+* `preview/index.html` — a browser player for every cue in the theme.
+* `Makefile` and `install.sh` for user-local and system-wide installation.
+
+### Fixed
+
+* Reverb is no longer applied uniformly: recurring cues are near-dry so that a
+  burst of notifications cannot pile up, while rare cues keep the full hall.
+* Added a bounded, loudness-aware normalisation stage so that sparse and dense
+  cues land at a comparable perceived level.