fix(PR Summaries): summarize each linked task.

[mikewuu]

Currently the linked task is referenced when getting a PR summary via :homie-summary:. The issue is sometimes the LLM only looks at code and doesn't offer any task context.

This task is to add a new section for closed / linked tasks and summarize each task

• [ ] add linked tasks section
• [ ] show url to task
• [ ] summarize task