feat: upgrade to donglora-client 0.2, simplify connection, fix org URLs

- Upgrade donglora-client from 0.1 to 0.2 (ping-on-connect validation)
- Remove manual mux/serial fallback and manual ping — handled by client now
- Fix repository/homepage URLs to github.com/donglora/bridge
- Fix README links to donglora GitHub org

CHANGELOG.md

@@ -1,5 +1,23 @@
 # Changelog
 
+## [0.3.0] - 2026-04-07
+
+### Changed
+
+- Upgraded to `donglora-client` 0.2: all connections now auto-validate via
+  ping-on-connect, rejecting non-DongLoRa serial devices within 200ms.
+- Simplified connection logic — removed manual mux/serial fallback and manual
+  ping; `donglora_client::connect()` handles the full fallback chain and
+  validation internally.
+- Config negotiation detects mux vs serial via transport type instead of
+  string comparison.
+
+### Fixed
+
+- Repository and homepage URLs now point to `github.com/donglora/bridge`
+  (was `swaits/donglora-bridge`).
+- README links updated to `donglora` GitHub org.
+
 ## [0.2.2] - 2026-04-06
 
 ### Fixed