Add experimental Dogechat bridge (based on bitchat-bridge)

.gitignore

@@ -14,3 +14,4 @@ cmake-*
 .cache
 .ccls
 compile_commands.json
+releases/

README.md

@@ -2,6 +2,13 @@
 
 MeshCore is a lightweight, portable C++ library that enables multi-hop packet routing for embedded projects using LoRa and other packet radios. It is designed for developers who want to create resilient, decentralized communication networks that work without the internet.
 
+## About the Dogechat Bridge
+
+This is a special experimental Dogechat bridge branch.
+
+Read [my blog](https://juraj.bednar.io/en/blog-en/2026/01/18/bridging-dogechat-and-meshcore-resilient-communication-when-you-need-it-most/) and [documentation](docs/dogechat-bridge.md).
+
+
 ## 🔍 What is MeshCore?
 
 MeshCore now supports a range of LoRa devices, allowing for easy flashing without the need to compile firmware manually. Users can flash a pre-built binary using tools like Adafruit ESPTool and interact with the network through a serial console.
@@ -97,10 +104,10 @@ Here are some general principals you should try to adhere to:
 
 There are a number of fairly major features in the pipeline, with no particular time-frames attached yet. In very rough chronological order:
 - [X] Companion radio: UI redesign
-- [ ] Repeater + Room Server: add ACL's (like Sensor Node has)
-- [ ] Standardise Bridge mode for repeaters
+- [X] Repeater + Room Server: add ACL's (like Sensor Node has)
+- [X] Standardise Bridge mode for repeaters
 - [ ] Repeater/Bridge: Standardise the Transport Codes for zoning/filtering
-- [ ] Core + Repeater: enhanced zero-hop neighbour discovery
+- [X] Core + Repeater: enhanced zero-hop neighbour discovery
 - [ ] Core: round-trip manual path support
 - [ ] Companion + Apps: support for multiple sub-meshes (and 'off-grid' client repeat mode)
 - [ ] Core + Apps: support for LZW message compression
@@ -113,12 +120,3 @@ There are a number of fairly major features in the pipeline, with no particular
 - Report bugs and request features on the [GitHub Issues](https://github.com/ripplebiz/MeshCore/issues) page.
 - Find additional guides and components on [my site](https://buymeacoffee.com/ripplebiz).
 - Join [MeshCore Discord](https://discord.gg/BMwCtwHj5V) to chat with the developers and get help from the community.
-
-## RAK Wireless Board Support in PlatformIO
-
-Before building/flashing the RAK4631 targets in this project, there is, unfortunately, some patching you have to do to your platformIO packages to make it work. There is a guide here on the process:
-   [RAK Wireless: How to Perform Installation of Board Support Package in PlatformIO](https://learn.rakwireless.com/hc/en-us/articles/26687276346775-How-To-Perform-Installation-of-Board-Support-Package-in-PlatformIO)
-
-After building, you will need to convert the output firmware.hex file into a .uf2 file you can copy over to your RAK4631 device (after doing a full erase) by using the command `uf2conv.py -f 0xADA52840 -c firmware.hex` with the python script available from:
-   [GitHub: Microsoft - uf2](https://github.com/Microsoft/uf2/blob/master/utils/uf2conv.py)
-

docs/dogechat-bridge.md

@@ -0,0 +1,148 @@
+# Dogechat Bridge
+
+The Dogechat Bridge enables communication between the [Dogechat](https://dogechat.app) Android app and MeshCore mesh network. Messages sent to the `#mesh` channel in Dogechat are relayed to MeshCore nodes, and vice versa.
+
+## Overview
+
+- **Bridge Direction**: Bidirectional - messages flow both ways between Dogechat and MeshCore
+- **Channel**: Only the `#mesh` channel is bridged (hardcoded)
+- **Identification**: Messages from Dogechat users appear with a phone emoji prefix on MeshCore nodes
+- **Platform**: ESP32 only (requires ESP32 ROM miniz for decompression)
+
+## Supported Boards
+
+The following ESP32 boards have `_companion_radio_usb_dogechat` targets:
+
+| Board | Target Name |
+|-------|-------------|
+| Heltec LoRa32 V2 | `Heltec_v2_companion_radio_usb_dogechat` |
+| Heltec LoRa32 V3 | `Heltec_v3_companion_radio_usb_dogechat` |
+| Heltec Wireless Stick Lite V3 | `Heltec_WSL3_companion_radio_usb_dogechat` |
+| Heltec CT62 | `Heltec_ct62_companion_radio_usb_dogechat` |
+| Heltec Tracker V2 | `heltec_tracker_v2_companion_radio_usb_dogechat` |
+| LilyGo T3-S3 (SX1262) | `LilyGo_T3S3_sx1262_companion_radio_usb_dogechat` |
+| LilyGo T-Deck | `LilyGo_TDeck_companion_radio_usb_dogechat` |
+| LilyGo TLora V2.1 | `LilyGo_TLora_V2_1_1_6_companion_radio_usb_dogechat` |
+| Station G2 | `Station_G2_companion_radio_usb_dogechat` |
+| Seeed Xiao C3 | `Xiao_C3_companion_radio_usb_dogechat` |
+| Seeed Xiao S3 WIO | `Xiao_S3_WIO_companion_radio_usb_dogechat` |
+| Ebyte EoRa-S3 | `Ebyte_EoRa-S3_companion_radio_usb_dogechat` |
+
+**Note**: NRF52-based boards are not supported because Dogechat message decompression requires the ESP32 ROM miniz library.
+
+## Build Targets
+
+### USB + Dogechat (`*_companion_radio_usb_dogechat`)
+
+This is the recommended configuration:
+
+- **MeshCore companion app**: Connects via USB serial
+- **Dogechat app**: Connects via standalone BLE
+
+This gives the best experience because:
+- The MeshCore web app works reliably via USB serial
+- Dogechat has dedicated BLE access without sharing with MeshCore
+
+### Building
+
+```bash
+# Build for Heltec Wireless Stick Lite V3
+pio run -e Heltec_WSL3_companion_radio_usb_dogechat
+
+# Flash
+pio run -e Heltec_WSL3_companion_radio_usb_dogechat -t upload
+```
+
+## How It Works
+
+### Channel Bridging
+
+1. **Dogechat to MeshCore**: When a Dogechat user sends a message to `#mesh`, the bridge:
+   - Receives the message via BLE
+   - Decompresses it (Dogechat uses zlib compression)
+   - Extracts the sender nickname and message content
+   - Sends it to the MeshCore #mesh with a phone emoji prefix
+
+2. **MeshCore to Dogechat**: When a MeshCore node sends a message to the `#mesh` channel, the bridge:
+   - Receives the mesh packet
+   - Creates a Dogechat MESSAGE packet with the sender name and content
+   - Broadcasts it via BLE
+
+### Message Format
+
+Messages from Dogechat appear on MeshCore as:
+```
+<sender>: message content
+```
+
+Messages from MeshCore appear on Dogechat with the MeshCore sender's name in angle brackets.
+
+### Long Messages
+
+MeshCore packets have a ~127-byte payload limit. Long Dogechat messages are automatically split into multiple parts with `[1/N]` indicators.
+
+## Limitations
+
+1. **Only #mesh channel**: Only the `#mesh` hashtag channel is bridged. DMs and other channels are ignored.
+
+2. **Message size**: MeshCore packets are limited to ~127 bytes. Long messages are split into multiple parts.
+
+3. **No end-to-end encryption bridge**: Dogechat's Noise protocol encryption and MeshCore's encryption are separate. Messages are decrypted/re-encrypted at the bridge.
+
+4. **No file/image transfer**: Dogechat file transfers (images, etc.) are not supported on the mesh.
+
+5. **Time synchronization**: The bridge synchronizes its clock from incoming Dogechat packets. If no Dogechat client connects, timestamps may be inaccurate. Time needs to be accurate for Dogechat to work
+
+## Debugging
+
+To enable debug output, use one of these methods:
+
+### Method 1: Environment variable (temporary)
+
+```bash
+# Build with debug output enabled
+PLATFORMIO_BUILD_FLAGS="-D DOGECHAT_DEBUG=1" pio run -e Heltec_WSL3_companion_radio_usb_dogechat
+```
+
+### Method 2: Edit platformio.ini (persistent)
+
+Add `-D DOGECHAT_DEBUG=1` to your environment's build_flags:
+
+```ini
+[env:Heltec_WSL3_companion_radio_usb_dogechat]
+build_flags =
+  ${Heltec_WSL3_companion_radio_usb.build_flags}
+  ${dogechat_base.build_flags}
+  -D DOGECHAT_DEBUG=1   ; Enable debug output
+```
+
+This enables detailed logging of:
+- Message parsing
+- Relay confirmations
+- Peer cache updates
+- Fragment reassembly
+
+## Technical Details
+
+### BLE Service
+
+- **Service UUID**: `F47B5E2D-4A9E-4C5A-9B3F-8E1D2C3A4B5C`
+- **Characteristic**: Single read/write/notify characteristic
+- **MTU**: 517 bytes (max BLE MTU for large messages)
+
+### Channel Key
+
+The `#mesh` channel uses a hashtag-derived key:
+```
+SHA256("#mesh")[0:16] = 5b664cde0b08b220612113db980650f3
+```
+
+This matches MeshCore's hashtag room key derivation.
+
+### Protocol Support
+
+- Message decompression (zlib via ESP32 ROM miniz)
+- Ed25519 message signing
+- Peer announcement/discovery
+- REQUEST_SYNC handling (sends cached messages)
+- Fragment reassembly for long messages