docs: Update CHANGELOG and bump version to 2.0.4

Test coverage increased to 93.92% (218 tests).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docs/CHANGELOG.md

@@ -2,6 +2,17 @@
 
 All notable changes to claude-hud will be documented in this file.
 
+## [2.0.4] - 2026-01-03
+
+### Improved
+- **Test coverage**: Increased to 93.92% (218 total tests)
+  - Added SessionStats hours format test
+  - Added transcript-reader invalidate test
+  - Added AgentList edge case tests (filename-only targets, truncation, empty targets)
+  - Added context-detector edge case tests (missing permissions, undefined cwd)
+
+---
+
 ## [2.0.3] - 2026-01-03
 
 ### Improved

tui/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claude-hud-tui",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "type": "module",
   "main": "dist/index.js",
   "scripts": {