Persist note listing so short numeric IDs work across invocations

[Copilot]

Note IDs (20260317-193750-042) are unwieldy to type. The listing already displayed numbers 1-N, but they were only usable within the same process — memo list then memo read 1 in a new shell would fail with "no current note listing".

Changes

• internal/storage/storage.go: Added SaveLastListing([]string) and LoadLastListing() — persists ordered note IDs to ~/.memo-notes/.last-listing
• cmd/list_command.go: Saves the listing to disk after each memo list run
• cmd/command.go: ResolveNoteID() falls back to the on-disk listing when the in-memory listing is empty, making numbers valid across invocations until the next memo list
• internal/ui/ui.go: Tip text updated to reflect persistence behavior

Usage

$ memo list
 1. Go Notes      | Created: 2026-03-17 10:00
 2. Python Basics | Created: 2026-03-17 10:01
 3. JavaScript    | Created: 2026-03-17 10:02

Tip: Numbers 1-3 stay valid until the next 'memo list' (e.g., 'memo read 3', 'memo delete 2').

$ memo read 2      # works in a new shell — no need to retype the full ID
$ memo delete 3

Original prompt

---

This section details on the original issue you should resolve

<issue_title>change up the note ids</issue_title>
<issue_description>need a way to make the typing of note_ids to be easier.
typing out the long note IDs is error-prone

need a way to simplify the list of the notes names and ids, maybe providing a temp id that can be typed the when note needs to be deleted, shown, edited....

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes change up the note ids #3

---

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.