Allow daemons to raise a signal upon autoexit

[shikokuchuo]

Closes #87

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (d53637f) 99.81% compared to head (1e71848) 99.81%. Report is 1 commits behind head on main.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #88 +/- ## ======================================= Coverage 99.81% 99.81% ======================================= Files 8 8 Lines 542 542 ======================================= Hits 541 541 Misses 1 1 ```

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