Polish README with badges and mermaid diagrams, add release infrastructure

Rewrite README with centered header, shields.io badges, mermaid topology
and session key diagrams, restructured installation section with Windows
quick start guide, and release documentation.

Add CHANGELOG.md for v0.2.0 and Gitea Actions release workflow that
builds source archives (tar.gz + zip) and publishes them on tag push.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CHANGELOG.md

@@ -0,0 +1,24 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/), and this project adheres to [Semantic Versioning](https://semver.org/).
+
+## [0.2.0] — 2026-02-26
+
+First tagged release. Includes the CLI statusline, standalone usage fetcher, cross-platform desktop widget, and installer wizard.
+
+### Added
+- **CLI Statusline** — headless status bar for Claude Code showing context window and token usage as text progress bars
+- **Usage Fetcher** — standalone Node.js cron job that fetches token usage from the Claude API and writes a shared JSON cache
+- **Desktop Widget** — cross-platform system tray icon (pystray) with circular progress bar, Claude starburst logo, and color-coded usage severity
+- **Installer Wizard** — interactive Python installer (`install_wizard.py`) with platform detection, component selection, cron/autostart setup, and session key configuration
+- **Windows support** — PowerShell installer wrapper (`install.ps1`) and Windows-compatible paths
+- **Session expiry warning** — statusline shows a warning when the session key is about to expire
+
+### Fixed
+- CRLF line ending issues on cross-platform installs
+- Tray icon visibility — switched to Claude orange with full opacity at larger size
+- Block comment syntax error in cron example
+
+[0.2.0]: https://git.davoryn.de/calic/claude-statusline/releases/tag/v0.2.0