Add edit command to notes tool

[Iter1993]

What

Adds an edit <id> <text> command to the notes tool, plus supporting scaffolding:

• lib/store.js — edit(id, text) looks up a note by id and replaces its text
• notes.js — new edit case, updated help text
• lib/config.js — SESSION_TIMEOUT_MINUTES setting
• tests/notes.test.js — tests for matches() (search)
• .github/workflows/ci.yml — run npm test on PRs
• .gitignore — ignore node_modules/ and notes.json

Test

npm test — 3 passing.

[Iter1993]

Review — bugs, edge cases, risk

🔴 Blocker: edit() crashes on an unknown id

lib/store.js

function edit(id, text) {
  const data = load();
  const note = data.notes.find((n) => n.id === id);
  note.text = text;   // note is undefined when nothing matches
  save(data);
}

Array.prototype.find returns undefined when no note has that id, so note.text = text throws:

$ node notes.js edit 999 "nope"
TypeError: Cannot set properties of undefined (setting 'text')
    at Object.edit (lib/store.js:51:13)

Every other command handles "not found": delete checks the return of remove() and prints No note #X found, search checks found.length === 0. edit has no guard, so any typo in the id crashes with a stack trace. node notes.js edit abc "x" hits the same path (id is NaN).

Fix: look before writing, and report the miss like delete does.

function edit(id, text) {
  const data = load();
  const note = data.notes.find((n) => n.id === id);
  if (!note) return false;
  note.text = text;
  save(data);
  return true;
}

case "edit": {
  const id = Number(rest[0]);
  const text = rest.slice(1).join(" ").trim();
  const ok = store.edit(id, text);
  console.log(ok ? `Updated note #${id}` : `No note #${id} found`);
  break;
}

🟠 edit accepts empty text and silently blanks the note

node notes.js edit 1 (no text) sets the note's text to "" and still prints Updated note #1. add rejects empty input (Usage: notes add <your note>); edit should be consistent and bail on empty text.

🟡 No test coverage for the new feature

tests/notes.test.js only exercises matches() (search). edit() — the actual change in this PR — has zero tests, which is why the crash above isn't caught by CI. Add cases for: edit an existing note, edit a missing id (should not throw), edit with empty text.

🟡 Dead config

config.SESSION_TIMEOUT_MINUTES is printed in the help text but nothing implements a session lock. Either drop it or note it's not wired up yet, so it isn't mistaken for a real feature.

Minor

• .github/workflows/ci.yml pins actions/checkout@v5 / actions/setup-node@v5 by major tag only; fine for a playground, but SHA-pinning is the safer habit.
• matches() search is case-sensitive ("Milk" won't match "milk"). Pre-existing, not introduced here.

[Iter1993]

Judgment: Claude caught the planted bug — store.edit() calls note.text = text without checking that find() returned a note, so node notes.js edit <unknown-id> ... throws TypeError: Cannot set properties of undefined. It also flagged the missing empty-text guard and the absent test coverage for edit().