docs: refine README presentation with banner and fork overview

README.md

@@ -1,11 +1,38 @@
-# OpenTracks — sensor-first fork
+# OpenTracks
 
-A customized fork of OpenTracks for sport tracking that prioritizes Bluetooth sensor measurements over GPS data.
+![Bluetooth sensors, recording, and activity export](docs/images/readme-banner.svg)
 
-**Upstream:** [OpenTracksApp/OpenTracks](https://codeberg.org/OpenTracksApp/OpenTracks).
-**Fork repository:** [karol/OpenTracks](https://gitea.labus.uk/karol/OpenTracks).
+**A sensor-first fork of OpenTracks.** Record sport activities with Bluetooth sensors taking priority over GPS, alongside customized recording controls and audio behavior.
 
-[Fork purpose](#fork-purpose) · [Changes from upstream](#changes-from-upstream) · [Requirements](#requirements) · [Getting started](#getting-started) · [Configuration](#configuration) · [Usage](#usage) · [Development](#development) · [Upstream maintenance](#upstream-maintenance) · [Documentation](#documentation) · [Credits](#credits) · [License](#license)
+| Project | Platform | Main change | License |
+| --- | --- | --- | --- |
+| Personal fork | Android 8.0+ | Bluetooth sensor priority | [Apache 2.0](LICENSE) |
+
+<p align="center">
+  <a href="https://gitea.labus.uk/karol/OpenTracks/releases"><strong>Download fork APKs</strong></a> ·
+  <a href="#getting-started">Build locally</a> ·
+  <a href="#changes-from-upstream">What changed</a> ·
+  <a href="README.upstream.md">Upstream documentation</a>
+</p>
+
+> **Fork identity** — [This repository](https://gitea.labus.uk/karol/OpenTracks) is based on [OpenTracksApp/OpenTracks](https://codeberg.org/OpenTracksApp/OpenTracks). Upstream store downloads do not include these modifications.
+
+<details>
+<summary>Browse all sections</summary>
+
+- [Fork purpose](#fork-purpose)
+- [Changes from upstream](#changes-from-upstream)
+- [Requirements](#requirements)
+- [Getting started](#getting-started)
+- [Configuration](#configuration)
+- [Usage](#usage)
+- [Development](#development)
+- [Upstream maintenance](#upstream-maintenance)
+- [Documentation](#documentation)
+- [Credits](#credits)
+- [License](#license)
+
+</details>
 
 ## Fork purpose
 
@@ -13,27 +40,35 @@ Use hardware sensors as the primary source of cadence, speed, and distance, with
 
 ## Changes from upstream
 
-- Bluetooth sensor data takes priority over GPS in the modified recording flow.
-- Expanded sensor settings and recording layouts.
-- Media controls in the statistics view.
-- Voice announcement and audio-focus changes.
-- Fork-specific application IDs, including `de.dennisguse.opentracks.fork` and its build variants.
+| Area | Changes maintained in this fork |
+| --- | --- |
+| **Recording** | Bluetooth sensor data takes priority over GPS in the modified recording flow. |
+| **Interface** | Expanded sensor settings and customized recording layouts. |
+| **Audio** | Media controls in the statistics view; voice announcement and audio-focus changes. |
+| **App identity** | Fork-specific application IDs, including `de.dennisguse.opentracks.fork` and its variants. |
 
 ## Requirements
 
-- Android 8.0/API 26 or later for the app, as configured in `build.gradle`.
-- Android SDK with platform 37 for builds.
-- The Gradle wrapper; daemon toolchain settings request JetBrains JDK 21 (`gradle/gradle-daemon-jvm.properties`).
+| Use | Requirements |
+| --- | --- |
+| **Run the app** | Android 8.0 / API 26 or later, as configured in `build.gradle`. |
+| **Build the app** | Android SDK platform 37 and the Gradle wrapper. The daemon toolchain requests JetBrains JDK 21 in `gradle/gradle-daemon-jvm.properties`. |
 
 ## Getting started
 
-Download this fork's APKs from [Gitea releases](https://gitea.labus.uk/karol/OpenTracks/releases), or build a debug APK from the repository root:
+### Install a build
+
+Download APKs from [this fork's Gitea releases](https://gitea.labus.uk/karol/OpenTracks/releases).
+
+### Build from source
+
+From the repository root:
 
 ```bash
 ./gradlew assembleIrreproducibleDebug
 ```
 
-Build output is under `build/outputs/apk/`. Store links in the inherited documentation distribute upstream OpenTracks and do not include this fork's changes.
+**Output:** `build/outputs/apk/`. The debug build is intended for development.
 
 ## Configuration
 
@@ -66,12 +101,13 @@ After an upstream merge, review sensor priority, recording layouts, announcement
 
 ## Documentation
 
-- [Inherited upstream README](README.upstream.md): retained from this checkout, with the local fork notice removed and malformed local links corrected.
-- [Dashboard API](README_API.md).
-- [Tested sensors](README_TESTED_SENSORS.md).
-- [Upstream release instructions](README_RELEASE.md): review before applying to this fork.
-
-[README style guide](docs/README-STYLE.md).
+| Reference | What you will find |
+| --- | --- |
+| [Inherited upstream README](README.upstream.md) | Original features, screenshots, export formats, and project history. Retained from this checkout; local fork notice removed and malformed links corrected. |
+| [Dashboard API](README_API.md) | Integration with external dashboards. |
+| [Tested sensors](README_TESTED_SENSORS.md) | Documented sensor compatibility. |
+| [Upstream release instructions](README_RELEASE.md) | Inherited release process; review before applying it to this fork. |
+| [README style guide](docs/README-STYLE.md) | Shared documentation structure and presentation rules. |
 
 ## Credits