chore: open v0.3.1-dev cycle on maint

Reset maint to v0.3.0 to retire the v0.2.x maintenance window and
open a new tracking branch for v0.3.1-dev bug-fix work.

- Cargo: 0.3.0 → 0.3.1-dev
- CHANGELOG: fresh [Unreleased] block above [0.3.0]
- README: badge v0.3.0 → v0.3.1--dev

CHANGELOG.md

@@ -5,6 +5,8 @@ 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]
+
 ## [0.3.0] - 2026-05-11
 
 ### Added

Cargo.lock

@@ -1052,7 +1052,7 @@ checksum = "9844ddc3a6e533d62bba727eb6c28b5d360921d5175e9ff0f1e621a5c590a4d5"
 
 [[package]]
 name = "fips"
-version = "0.3.0"
+version = "0.3.1-dev"
 dependencies = [
  "bech32",
  "bluer",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fips"
-version = "0.3.0"
+version = "0.3.1-dev"
 edition = "2024"
 description = "A distributed, decentralized network routing protocol for mesh nodes connecting over arbitrary transports"
 license = "MIT"

README.md

@@ -3,7 +3,7 @@
 ![banner](docs/logos/fips_banner.png)
 [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
 [![Rust](https://img.shields.io/badge/rust-1.85%2B-orange.svg)](https://www.rust-lang.org/)
-[![Status](https://img.shields.io/badge/status-v0.3.0-green.svg)](#status--roadmap)
+[![Status](https://img.shields.io/badge/status-v0.3.1--dev-green.svg)](#status--roadmap)
 
 A self-organizing encrypted mesh network built on Nostr identities,
 capable of operating over arbitrary transports without central