test(morse): add missing coverage for DEFAULT_WPM, DEFAULT_TIMING, and derived timing fields

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/lib/morse.test.ts

@@ -4,6 +4,8 @@ import {
   NOVICE_LETTERS,
   OPERATOR_WORDS,
   wpmToTiming,
+  DEFAULT_WPM,
+  DEFAULT_TIMING,
   validatePhrase,
   pickChallenge,
 } from './morse'
@@ -37,6 +39,13 @@ describe('OPERATOR_WORDS', () => {
   })
 })
 
+describe('DEFAULT_WPM and DEFAULT_TIMING', () => {
+  it('DEFAULT_WPM is 10', () => expect(DEFAULT_WPM).toBe(10))
+  it('DEFAULT_TIMING equals wpmToTiming(10)', () => {
+    expect(DEFAULT_TIMING).toEqual(wpmToTiming(10))
+  })
+})
+
 describe('wpmToTiming', () => {
   it('10 WPM gives dot=120ms', () => {
     expect(wpmToTiming(10).dot).toBe(120)
@@ -48,6 +57,18 @@ describe('wpmToTiming', () => {
   it('20 WPM gives dot=60ms', () => {
     expect(wpmToTiming(20).dot).toBe(60)
   })
+  it('elementGap equals dot', () => {
+    const t = wpmToTiming(10)
+    expect(t.elementGap).toBe(t.dot)
+  })
+  it('charGap is 3x dot', () => {
+    const t = wpmToTiming(10)
+    expect(t.charGap).toBe(t.dot * 3)
+  })
+  it('wordGap is 7x dot', () => {
+    const t = wpmToTiming(10)
+    expect(t.wordGap).toBe(t.dot * 7)
+  })
 })
 
 describe('validatePhrase', () => {

client/src/lib/morse.ts

@@ -85,7 +85,7 @@ export function pickChallenge(
 
   const weights = available.map(item => {
     const s = stats[item]
-    if (!s || s.attempts === 0) return 2
+    if (!s || s.attempts === 0) return 2 // unseen: prioritise over even 0%-accuracy items
     const accuracy = s.correct / s.attempts
     return Math.max(0.1, 1 - accuracy) + 0.1
   })