Rewrite README for OpenView 3; refresh screenshots

- Correct the transport matrix: HealthyPi 5 and both Sensythings speak
  USB + BLE + Wi-Fi (the old text claimed BLE was Sensything-only)
- Document Device Manager (SMP/MCUmgr), Console, Developer and replay
- Add a per-board support table, build-from-source and add-a-board sections
- Replace the OpenView 2 screenshots with current OpenView 3 captures
  (desktop Live view, iPad landscape)

Author: awhitchurch

README.md

@@ -1,87 +1,151 @@
 <div align="center">
 
-![Protocentral Logo](docs/images/protocentral.png)
+![ProtoCentral](docs/images/protocentral.png)
 
 # OpenView 3
 
+**The companion app for ProtoCentral biosignal and sensor boards.**
+Stream live data over USB, BLE or Wi-Fi · visualize it in real time · record it to `.hpd` · replay it later.
 
-OpenView 3 is a companion application to receive data from various ProtoCentral boards. It visualizes the data in real-time and records it to `.hpd` (BIOSIG) files for later replay.
+[![Release builds](https://github.com/Protocentral/protocentral_openview/actions/workflows/release.yml/badge.svg)](https://github.com/Protocentral/protocentral_openview/actions/workflows/release.yml)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](#license)
 
-![Openview Desktop App](docs/images/openview-screen-desktop.png)
+[**Download**](https://github.com/Protocentral/protocentral_openview/releases) · [Supported boards](#supported-boards) · [Build from source](#build-from-source) · [Add your own board](#add-your-own-board)
 
-![Openview Mobile App](docs/images/openview-screen-mobile.jpg)
+![OpenView live view](docs/images/openview-live-desktop.png)
+
+*Live view — HealthyPi 5 streaming ECG, BioZ/respiration and PPG over BLE*
 
 </div>
 
-OpenView 3 is the current, primary supported app for all ProtoCentral boards. Built on the [Flutter framework](https://flutter.dev/), it runs on Windows, macOS, Linux, Android, and iOS.
+---
+
+## What it does
+
+OpenView 3 is a single app for every ProtoCentral board. It receives framed data from
+the board, decodes it into signals, plots it live, and writes it to `.hpd` (BIOSIG v1)
+files that round-trip with HealthyPi Studio.
+
+It runs on **Windows, macOS, Linux, Android and iOS** from one Flutter codebase.
 
-This repository is the canonical home of OpenView across versions. Earlier releases remain available: OpenView 2 lives on the [`v2` branch](https://github.com/Protocentral/protocentral_openview/tree/v2) (and its releases are tagged `2.x`), and the original Processing-based OpenView 1 is archived at [protocentral_openview_processing](https://github.com/Protocentral/protocentral_openview_processing).
+| | |
+|---|---|
+| **Live view** | Real-time plots of every channel the board exposes, with derived vitals (heart rate, SpO₂, respiration, temperature) shown alongside. |
+| **Record & replay** | One-click recording to `.hpd`, a built-in recordings browser, and a replay screen that scrubs through past sessions. |
+| **Device Manager** | Firmware and file management for any SMP/MCUmgr-enabled device over BLE — read image slots, upload firmware, browse the device filesystem. |
+| **Console** | Raw packet stream with hex dump, including packets the app doesn't recognize — the first place to look when bringing up new firmware. |
+| **Developer** | An unfiltered BLE GATT browser for poking at services and characteristics during bring-up. |
 
-OpenView 3 connects over three transports:
+## Connecting
 
-* **USB/UART** — desktop only; supported by every board.
-* **BLE** — currently available only for the **Sensything** family.
-* **Wi-Fi (TCP)** — currently available only for the **Sensything** and **HealthyPi** families.
+Three transports, gated per board — the app only offers what the board actually speaks.
 
-## Features:
+| Transport | Availability |
+|---|---|
+| **USB / UART** | Every board. **Desktop only** (Windows, macOS, Linux). |
+| **BLE** | HealthyPi 5, Sensything OX, Sensything CAP. All platforms. |
+| **Wi-Fi (TCP)** | HealthyPi 5, Sensything OX, Sensything CAP. Enter `host:port` manually. |
 
-* Multiple boards, one unified interface
-* Mobile platforms: Android and iOS
-* Desktop platforms: Windows, macOS, and Linux
-* USB, BLE, and Wi-Fi connectivity
-* Code development environment: [Flutter](https://flutter.dev/)
-* Records to `.hpd` (BIOSIG) files, round-trip compatible with HealthyPi Studio
-* You can add your own board by declaring a descriptor in the source (see `lib/boards/`)
+## Supported boards
 
-## Supported Boards
-* [HealthyPi 5](https://protocentral.com/product/healthypi-5-vital-signs-monitoring-hat-kit/)
-* ProtoCentral Sensything (OX and CAP)
-* AFE breakouts: ADS1292R, ADS1293, AFE4490, MAX30001, MAX30003, MAX86150, Pulse Express, TinyGSR
-* [TMF8829](https://protocentral.com/) dToF depth-ranging
+| Board | USB | BLE | Wi-Fi |
+|---|:--:|:--:|:--:|
+| [HealthyPi 5](https://protocentral.com/product/healthypi-5-vital-signs-monitoring-hat-kit/) | ✅ | ✅ | ✅ |
+| Sensything OX | ✅ | ✅ | ✅ |
+| Sensything CAP | ✅ | ✅ | ✅ |
+| ADS1292R · ADS1293 · AFE4490 | ✅ | — | — |
+| MAX30001 · MAX30003 · MAX86150 | ✅ | — | — |
+| Pulse Express · TinyGSR | ✅ | — | — |
+| TMF8829 dToF (depth map) | ✅ | — | — |
 
-## Installing and using ProtoCentral OpenView 3
+Don't see your board? It takes three files and no changes to the app — see
+[Add your own board](#add-your-own-board).
 
-You can download the latest version for your operating system from the [Releases](https://github.com/Protocentral/protocentral_openview/releases) page.
+## Install
 
-OpenView 3 is written in [Flutter](https://flutter.dev/) and is fully open source. You can compile your own from the source code provided in this GitHub repository.
+### Desktop
+
+Download the zip for your OS from the [Releases](https://github.com/Protocentral/protocentral_openview/releases)
+page, extract it, and run the app.
+
+### Mobile
+
+<div align="center">
 
-### Using on Desktop Platforms:
+[![Google Play](docs/images/play_store.png)](https://play.google.com/store/apps/details?id=com.protocentral.openview) [![App Store](docs/images/appstore.png)](https://apps.apple.com/fi/app/openview/id1667747246)
 
-1. Download the zip file from the [Releases](https://github.com/Protocentral/protocentral_openview/releases) page.
-2. Extract the zip file installed
-3. Open the app in the folder extracted and run the application
+</div>
 
-### Using on Mobile Platforms:
+> **Note** — USB is not available on mobile. Use BLE or Wi-Fi.
 
-Download the openview app from the [Google Play](https://play.google.com/store/apps/details?id=com.protocentral.openview) store for Android and from the [Apple App Store](https://apps.apple.com/fi/app/openview/id1667747246) for iOS.
+## Screenshots
 
+The same app, the same layout, everywhere — the navigation rail collapses to a bottom bar
+on phones.
 
 <div align="center">
 
-[![Download from Google Play](docs/images/play_store.png)](https://play.google.com/store/apps/details?id=com.protocentral.openview) [![Download from App Store](docs/images/appstore.png)](https://apps.apple.com/fi/app/openview/id1667747246)
+![OpenView on iPad](docs/images/openview-ipad.png)
+
+*OpenView 3 on iPad (landscape)*
+
 </div>
 
-## Packet Format
+## Build from source
+
+OpenView 3 is written in [Flutter](https://flutter.dev/) and is fully open source.
+
+```bash
+git clone https://github.com/Protocentral/protocentral_openview.git
+cd protocentral_openview
+flutter pub get
+flutter run -d macos      # or windows / linux / <device-id>
+```
+
+Release builds:
+
+```bash
+flutter build macos       # or windows / linux / apk / ios
+```
+
+Linux additionally needs `libudev-dev`, `libgtk-3-dev`, `clang`, `cmake`, `ninja-build`
+and `pkg-config`. See [.github/workflows/release.yml](.github/workflows/release.yml)
+for the exact toolchain each platform is built with.
+
+## Add your own board
+
+A board is **declared, not coded**. Adding one touches three files and needs no changes
+to the transport, protocol, UI or recording layers:
 
-ProtoCentral OpenView 3 is compatible with any device that can send data through a serial port over UART/USB/Bluetooth-SPP/BLE
+1. Declare a `BoardDescriptor` in `lib/boards/descriptors/<board>.dart` — its channels,
+   packets, commands, and which transports it speaks.
+2. Write pure decoder functions in `lib/boards/decoders/<board>_decoders.dart`
+   (`Uint8List payload → DecodedPacket`).
+3. Register the descriptor in `BoardRegistry.all`.
 
-| Position      |   Value   |
-| ---------     | ----------|
-| 0             |   0x0A    | 
-| 1             |   0xFA    |
-| 2             |   Payload Length LSB  |
-| 3             |   Payload Length MSB  |
-| 4             |   0x02 (Type - Data)  |
-| 5             |   Payload 0           |
-| ..            |   Payload (...)       |
-|   n           |   Payload n+5         |
-| (PL Len + 5)  |   0x0B                |
+See [docs/ARCHITECTURE.md](docs/ARCHITECTURE.md) for the full data path
+(Transport → Framer → Router → buffers → UI → Recorder).
 
-For Healthypi 5 firmware version 1.0.0 and above, the data (ECG, Bioz and PPG) are sent as seperate packets. Below are the respective packet formats
+## Wire format
+
+Any device that can push bytes over UART/USB/BLE can talk to OpenView. The frame is:
+
+| Position | Value |
+|---|---|
+| 0 | `0x0A` (start) |
+| 1 | `0xFA` (type indicator) |
+| 2 | Payload length LSB |
+| 3 | Payload length MSB |
+| 4 | Packet type |
+| 5 … n | Payload |
+| last | `0x0B` (stop) |
+
+<details>
+<summary><b>HealthyPi 5 packet layouts</b> (firmware ≥ 1.0.0 sends ECG/BioZ and PPG as separate packets)</summary>
 
 ```mermaid
   packet-beta
-  title Openview ECG & Bioz Packet
+  title OpenView ECG & BioZ packet
    0-7: "0x0A (START)"
    8-15: "0xFA (Type Indicator)"
    16-23: "Payload Length LSB"
@@ -107,7 +171,7 @@ For Healthypi 5 firmware version 1.0.0 and above, the data (ECG, Bioz and PPG) a
 
 ```mermaid
   packet-beta
-  title Openview PPG Packet
+  title OpenView PPG packet
     0-7: "0x0A (START)"
     8-15: "0xFA (Type Indicator)"
     16-23: "Payload Length LSB"
@@ -127,13 +191,43 @@ For Healthypi 5 firmware version 1.0.0 and above, the data (ECG, Bioz and PPG) a
     200-207: "0x0B (STOP)"
 ```
 
-# License
+</details>
+
+The TMF8829 depth-frame format is documented separately in
+[docs/protocols/tmf8829-wire-format.md](docs/protocols/tmf8829-wire-format.md).
+
+## Recording format
+
+Recordings are written as `.hpd` files (BIOSIG v1) — a block-based, append-only format
+that is binary-compatible with **HealthyPi Studio**, so files move freely between the
+two apps.
+
+## Device Manager (SMP / MCUmgr)
+
+OpenView can manage any device that exposes the standard SMP service over BLE, built on
+the [`mcumgr_dart`](https://pub.dev/packages/mcumgr_dart) package:
+
+- **Device info** — echo, task/memory stats, image slots
+- **Firmware** — list images and upload new ones
+- **Files** — browse and transfer files on the device filesystem
+
+> **Firmware upload works; the full DFU install flow (upload → test → reset → confirm)
+> is still work-in-progress and labelled as advanced use in the app.**
+
+## Version history
+
+OpenView has been through three generations. This repository is the canonical home for
+all of them:
 
-This software is open source and licensed under the following license:
+| Version | Stack | Where |
+|---|---|---|
+| **OpenView 3** *(current)* | Flutter | `main` — this branch |
+| OpenView 2 | Flutter | [`v2` branch](https://github.com/Protocentral/protocentral_openview/tree/v2), releases tagged `2.x` |
+| OpenView 1 | Processing | [protocentral_openview_processing](https://github.com/Protocentral/protocentral_openview_processing) (archived) |
 
-MIT License
+## License
 
-Copyright (c) 2019 Protocentral
+MIT License — Copyright (c) 2019 ProtoCentral
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal