Replaces the plain textarea with a WYSIWYG contenteditable editor so
the formatting the parent sees while writing matches what the student
sees when reading. Toolbar supports bold, italic, underline, H2/H3,
bullet/numbered lists, links, and YouTube embeds. Selection is saved
on editor blur and restored before each execCommand so toolbar clicks
don't lose the user's selection.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Practice: fire streak badge, first-letter hint on wrong answers, missed-words drill session after practice completes.
Test: audio-only mode with listening state before input appears, larger re-read button.
Words: definition field (DB migration + admin editor + TTS playback).
TTS: replace speechSynthesis with local Piper via /api/tts, WAV cached in data/tts-cache, falls back to browser voice when Piper is not installed.
Dockerfile: switched to node:26-slim, installs Piper binary + en_US-lessac-medium voice.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Nate EmmertandClaude Sonnet 4.6