Edit and delete global blockers/action items

[kacheo]

Problem

Day-file bullets support rm and update, but global blockers/action items can only be added and resolved — there's no way to fix a typo or delete one created by mistake.

Proposal

Add edit/delete parity for global items:

• devlog update-item <id> "new text" (or similar) to edit an item's text/fields
• devlog rm-item <id> to delete one

Reuse the existing items.yaml store, which already matches items by full UUID or 8-char prefix.

Note

Consider naming/UX so it's clear these operate on the global item store, not day-file sections (which already have rm/update).