feat(curator): Tatoeba's sentences as examples in every new language

JMdict brings Tatoeba's sentences for Japanese; the other languages'
dictionaries had none (CC-CEDICT) or Wiktionary's own, often
quotations. Each file now takes Tatoeba's sentences of the week (its
per-language exports, CC BY 2.0 FR) as its entries' first examples,
which become a card's hints: each sentence with a translation into the
dictionary's meaning language goes to the entries its words find, cut
as the app cuts a line of subtitles (at spaces, Korean's particles off,
Chinese by its longest words), up to three for each, those using the
word as its headword writes it first (Haus rather than zu Hause; 学习
rather than 學習 in the simplified dictionary), then those nearest seven
words long. German's common words nearly all get some (8,849 of
9,292), in ten seconds and under 300 MB; a dictionary whose sentences
can't be had keeps its words. `curate tatoeba` does the same for a file
made by hand.

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/tatoeba-eng_sentences.tsv

@@ -0,0 +1,17 @@
+24278	eng	The house is on fire.
+68954	eng	Are you studying?
+69521	eng	Are you a student?
+309992	eng	She studies mathematics.
+462934	eng	The street is wet.
+750342	eng	I study.
+1098492	eng	I ate.
+1364167	eng	In which street?
+1549913	eng	Hello, old friend!
+2203598	eng	Who ate?
+5222666	eng	On what street?
+8105184	eng	Mary works at a flower shop.
+8257152	eng	He is in the house.
+8475487	eng	He ate.
+9848192	eng	I learn.
+10268745	eng	I'll do it at home.
+13139893	eng	It is the street.