docs: add initial CHANGELOG and reference it in README

CHANGELOG.md

@@ -0,0 +1,54 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [1.0.0-alpha01] - 2026-07-08
+
+First public release of **Chom Bev e Brezhoneg**.
+
+### Added
+
+#### Listening
+
+- Record list of the *Chom Bev* audio course, with an emoji, the Breton title and
+  its French translation for each record.
+- Audio player with play/pause/replay, a seekable progress bar, and
+  previous/next-sentence navigation.
+- Playback speed control (with visual indicator when playback is modified) and a
+  configurable break between phrases to leave time to repeat.
+
+#### Subtitles
+
+- Synchronised subtitles (LRC format): Breton transcription and French
+  translation, highlighted line by line during playback.
+- Tap a sentence to seek straight to it; the list re-centers smoothly.
+- Subtitle preferences: show/hide transcription and translation, adjustable text
+  size, and phonetic markers (muted consonants and liaisons).
+- Preferences persist across sessions.
+
+#### Web pages
+
+- "Deepen" and "About" pages embedded in the app, matching the light/dark theme,
+  with a loading overlay and a bundled offline fallback when the network is
+  unavailable.
+
+#### Platforms & app
+
+- Targets Android, iOS, Desktop (JVM) and Web (JS + Wasm), all sharing the same
+  Compose Multiplatform UI. Only Android has been deeply tested for this version.
+- Audio playback backed by ExoPlayer (Android), AVFoundation (iOS), the browser
+  audio APIs (Web) and VorbisSPI (Desktop).
+- Light and dark themes; interface localised in French and Breton.
+- Modular architecture: `core`, `data` and `feature` modules glued by a thin
+  `shared` module, with Koin dependency injection validated at build time.
+- Crash reporting through GlitchTip (opt-in via `local.properties`, disabled
+  otherwise).
+- Released under the Apache 2.0 license.
+
+[Unreleased]: https://git.kaz.bzh/Antoine_Jaury_KSK/Chom-Bev-e-Brezhoneg/-/compare/v1.0.0-alpha01...main
+[1.0.0-alpha01]: https://git.kaz.bzh/Antoine_Jaury_KSK/Chom-Bev-e-Brezhoneg/-/tags/v1.0.0-alpha01

README.md

@@ -3,6 +3,8 @@
 This is a Compose Multiplatform project to listen to Breton from Vannes country. It uses an audio
 player adapted for each platform and synchronised subtitles.
 
+Notable changes between versions are documented in the [CHANGELOG](CHANGELOG.md).
+
 ## Main architecture
 
 This is a Kotlin Multiplatform project targeting Android, iOS, Web, Desktop (JVM).