chore: prepare release v0.3.0

- Update version to 0.3.0 in self_update_checker.ml
- Finalize CHANGELOG.md for 0.3.0 release with date 2026-02-11

Author: vch9

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ## [Unreleased]
 
+## [0.3.0] - 2026-02-11
+
 ### Added
 
 - **RPC Browser streaming**: Monitor/streaming RPC endpoints (e.g., `/monitor/heads/main`) now display live-updating content instead of timing out. Streaming is detected automatically and uses the pager's streaming mode with incremental JSON syntax highlighting.

src/self_update_checker.ml

@@ -8,7 +8,7 @@
 open Rresult
 
 (** Current version - kept in sync with main.ml *)
-let current_version = "0.2.1"
+let current_version = "0.3.0"
 
 (** GitHub repository info *)
 let github_owner = "trilitech"