fix(curator): HSK levels by the syllabus's tones; variants find their word

The syllabus's reading is matched with its tones first, so 和 hé gets
HSK 1 and 和 hè doesn't; only where no entry of a word reads it so (the
syllabus marks the tone changes of 一 and 不, 一下 yíxià, CC-CEDICT
doesn't) are the letters alone compared. CC-CEDICT's 2,885 entries that
are only "variant of …" (咊, an old variant of 和) are no entries of
their own any more, which repeated their word in the simplified file,
but written forms of that word, finding it in text and searches.

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

halkyon_learn_curator/test/fixtures/README.md

@@ -40,7 +40,7 @@ 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 16 of its lines (MDBG's file of
-2026-10-13): 中国, 了, 女儿, 学习, 书, 熊猫, 略, 的, 说 and 银行, with their
-readings. CC-CEDICT is by MDBG and its contributors, CC BY-SA 4.0
+`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>).