chore: Halkyon Learn moves into apps/learn

Its server, client, app and curator, and the tools that write its
assets (maps, Anki fixtures, icons), as they are; paths are fixed in
the commits that follow.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/learn/halkyon_learn_curator/test/fixtures/README.md

@@ -0,0 +1,80 @@
+# Test data
+
+`jmdict-eng-sample.json` holds six entries of JMdict 3.6.2 (2026-10-05) as
+jmdict-simplified writes it (<https://github.com/scriptin/jmdict-simplified>):
+JMdict is © the Electronic Dictionary Research and Development Group, used under
+its licence, CC BY-SA 4.0 (<https://www.edrdg.org/edrdg/licence.html>).
+
+`jlpt/` holds a few rows of the JLPT lists of yomitan-jlpt-vocab
+(<https://github.com/stephenmk/yomitan-jlpt-vocab>), CC BY-SA 4.0, from Jonathan
+Waller's lists (<http://www.tanos.co.uk/jlpt/>), CC BY; one row without an id is
+made up.
+
+`kanjidic2-sample.xml` holds five characters of KANJIDIC2 (database version
+2026-282) with its header and a shortened DTD: KANJIDIC2 is © the Electronic
+Dictionary Research and Development Group, used under its licence, CC BY-SA 4.0
+(<https://www.edrdg.org/edrdg/licence.html>).
+
+`kanji-data-sample.json` holds four entries of kanji-data's `kanji.json`
+(<https://github.com/davidluzgouveia/kanji-data>), cut to their numbers, from
+KANJIDIC2 and from Jonathan Waller's JLPT levels (<http://www.tanos.co.uk/jlpt/>),
+CC BY.
+
+`kanjivg-sample.xml` holds four characters of KanjiVG (the release of
+2026-07-14) with its notice, among them 橅, whose entry names itself 機:
+KanjiVG is © Ulrich Apel, CC BY-SA 3.0 (<https://kanjivg.tagaini.net>).
+
+`jmdict-e-examp-sample.xml` holds five entries of EDRDG's `JMdict_e_examp.gz`
+of 2026-10-09 (JMdict with Tatoeba's sentences, CC BY 2.0 FR) and the
+declarations of the entities they use: JMdict is © the Electronic Dictionary
+Research and Development Group, used under its licence, CC BY-SA 4.0
+(<https://www.edrdg.org/edrdg/licence.html>).
+
+`wiktionary-sample.jsonl` holds 31 lines of kaikki.org's Wiktextract data of the
+English Wiktionary (the dump of 2026-10-03, read per word from kaikki.org): the
+German Haus, Häuser, Häusern, essen, aß, gegessen, Straße and im, the Greek σπίτι,
+σπιτιού and γράφω, the English house, houses, go and went, the French maison,
+the Korean 먹다, 집 and 학생, and the Korean entry of the Han character 水 (its readings,
+물 수), each shortened to the fields the curator reads (no categories,
+etymologies or related words; at most six senses, two examples, 40 forms, two
+sounds, and 14 translations, those into German and Greek). Wiktionary's text is
+by its contributors, CC BY-SA 4.0 (<https://en.wiktionary.org/wiki/Wiktionary:Copyrights>);
+the extraction is Tatu Ylonen's Wiktextract (<https://kaikki.org>).
+
+`cedict-sample.txt` holds CC-CEDICT's header and 23 of its lines (MDBG's file of
+2026-10-13): 中国, 了, 女儿, 学习, 书, 熊猫, 略, 的, 说, 银行, 和 and 咊, an old
+variant of 和, with their readings. CC-CEDICT is by MDBG and its contributors, CC BY-SA 4.0
+(<https://www.mdbg.net/chinese/dictionary?page=cc-cedict>).
+
+`tatoeba-*.tsv` hold a few lines of Tatoeba's exports of 2026-10-10
+(<https://downloads.tatoeba.org/exports/per_language/>): German, Chinese and
+Korean sentences using Haus, aß, Straße, 学习, 집에서 and 학생이 (and one of each
+without an English translation), the links to their English translations, and
+those translations. The sentences are by Tatoeba's contributors, CC BY 2.0 FR
+(<https://tatoeba.org/en/terms_of_use>).
+
+`unihan-sample.txt` holds the lines of Unihan 18.0.0 (2026-07-31,
+<https://www.unicode.org/Public/UCD/latest/ucd/Unihan.zip>) the curator reads for
+水, 说, 說, 説, 這, 这, 了, 瞭, 后, 後, 行, 们, 們, 学 and 學, with a header like its
+files'. The Unihan Database is © Unicode, Inc., under the Unicode License v3
+(<https://www.unicode.org/license.txt>).
+
+`cedict-characters-sample.txt` holds 17 lines of CC-CEDICT (MDBG's file of
+2026-10-14) for the words those characters write (這, 了, 瞭, 瞭解, 為了, 後, 后,
+以後, 皇后, 們, 我們, 說, 水, 行, 銀行, 學 and 學習), CC BY-SA 4.0 as above.
+
+`krdict-sample.json` holds six entries of KRDict's JSON export of 2026-09-19
+(<https://krdict.korean.go.kr/download/downloadPopup>): 같이 (the adverb and the
+particle), 가다 with its proverb 가는 날이 장날, 읽다 and 학교, each cut to its first
+three senses, their English and Japanese equivalents and two examples, without
+sound files or related words. 한국어기초사전 is by the National Institute of
+Korean Language (국립국어원), CC BY-SA 2.0 KR
+(<https://krdict.korean.go.kr/kboardPolicy/copyRightTermsInfo>).
+
+`makemeahanzi-graphics-sample.txt` and `makemeahanzi-dictionary-sample.txt` hold
+the lines of Make Me a Hanzi's `graphics.txt` and `dictionary.txt` (commit
+`618dbab`, 2018-10-16, <https://github.com/skishore/makemeahanzi>) for 水 and 海.
+The strokes derive from the fonts Arphic PL KaitiM GB and Arphic PL UKai, © 1999
+Arphic Technology Co., Ltd., under the Arphic Public License (its text is in the
+app's `assets/makemeahanzi/ARPHICPL.TXT`); the dictionary's lines are under the
+LGPL, version 3 or later (`assets/makemeahanzi/LGPL.txt`).