Release v0.7.6

castiel - v0.7.6

This PR fixes five important bugs across castiel, including tool-call and failure logging, MCP ping timeouts, chat history navigation, debug mode in development, and live runtime updates for background processes and sub-agents. It also includes dependency updates and several small runtime and UI improvements.

• Bug fix/chat by @ISO53 in #14

Full Changelog: v0.7.1...v0.7.6