CLI App Clear Updates

`ed app clear-updates`

Deletes the record of past update checks.

ed app clear-updates [--yes] [--json]

Name	Type / values	Default	What it does
`--yes`	flag	off	Delete the history. Without it, print the plan only.
`--json`	flag	off	Emit JSON on stdout.

Without --yes, --json describes the safe preview, where removed is how many checks would be removed:

{
  "action": "clear update history",
  "applied": false,
  "changed": false,
  "removed": 42,
  "targets": ["/Users/me/Library/Application Support/Edith/update-checks.json"]
}

With --yes, applied is true and changed says whether the log contained any checks.

Examples:

ed app clear-updates
ed app clear-updates --yes
ed app clear-updates --yes --json

Without --yes it prints the history file it would clear and changes nothing. With --yes and without --json it prints cleared 42 check(s). This is the clear button in the update schedule sheet. It counts the file, deletes it, and exits 0 whether or not there was anything to delete, reporting cleared 0 check(s) in the empty case. The file is removed outright rather than moved to the Trash. Nothing else is touched, and neither process needs to be running.