Bump version to 0.4.0 for release

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

Author: himattm

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "agent-task-queue"
-version = "0.3.2"
+version = "0.4.0"
 description = "MCP server for sequential task execution via FIFO queue"
 readme = "README.md"
 requires-python = ">=3.10"