release: v1.2.0 - Pure Go update engine, enhanced journal log fetcher, and protocol concurrency fixes

CHANGELOG.md

@@ -0,0 +1,25 @@
+# Changelog
+
+All notable changes to the `theta-agent` daemon will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [v1.2.0] - 2026-08-03
+
+### Added
+- **Protocol v1.1.0 Compliance**: Full alignment with `PROTOCOL.md` (v1.1.0) specification.
+- **Ed25519 Cryptographic Verification**: Verification of Ed25519 Base64 signatures for high-risk C2 commands (`reboot`, `service_restart`, `configure_ldap`, `arbitrary_bash`, `update_binary`).
+- **Enhanced Journal Log Fetcher (`fetch_logs`)**: Support for querying service-specific systemd logs (`service` parameter) with configurable line count (`lines` parameter).
+- **Pure Go Self-Update Engine (`update_binary`)**: Replaced shell script execution with pure Go HTTP client fetching, SHA256 verification, atomic file replacement, and clean daemon restart.
+
+### Fixed
+- **Goroutine Leak Prevention**: Added `stopCh` lifecycle management to terminate background telemetry and heartbeat tickers upon WebSocket disconnection.
+- **Dynamic Config Rerenders**: Resolved data races when toggling capabilities or reloading `agent.yml` via `reload_config`.
+- **Config Path Uniformity**: Standardized canonical configuration file path across codebase, installer, and documentation to `/etc/theta42/agent.yml`.
+
+## [v0.1.0] - 2026-08-01
+
+### Added
+- Initial release of `theta-agent` Go daemon replacing legacy bash metric scripts.
+- Persistent outbound WebSocket telemetry and local capability matrix enforcement.