hanja: add single-character dictionary data

docs/PROVENANCE.md

@@ -14,6 +14,27 @@ carry a separate data license.  `map/telex.map` is generated by
 `map/emoji.dict` is generated deterministically from the repository-maintained
 `map/emoji.src` by `map/mkemoji`.  No external dataset is required.
 
+`map/hanja.src` is a single-character subset of libhangul's
+`data/hanja/hanja.txt` from release tag `libhangul-0.2.0`.  Its immutable
+identifiers are:
+
+- annotated tag object: `20afc38922e3595ee3ed5b186f2ea05afe663763`
+- peeled commit: `41c702f5d3581325b646ef6249f1f641b0427ae0`
+- input blob: `199cfd70c4b306257ac2e018714a1285f7cf0ed3`
+- input SHA-256: `dd44dcc856cf542b1022d0f39c2e9b9f8805fdcc5923be80f04849ed97ce0996`
+
+`map/libhangul2hanja` keeps only a one-syllable modern Hangul reading paired
+with one BMP Hanja rune supported by the popup.  It writes one
+`Hanja<TAB>Hangul syllable` pair per row in upstream order; word entries are
+not part of this data.  `map/mkhanja` groups those rows by reading for the
+runtime dictionary without changing candidate order, retaining the first 32
+candidates supported by the engine.  Exact import and regeneration commands
+are in `map/README`.
+
+The upstream data header is BSD 3-Clause licensed, copyright 2005, 2006 Choe
+Hwanjin.  Its complete license text is in
+`LICENSES/BSD-3-Clause-libhangul-hanja.txt`.
+
 `map/kanji.dict` identifies itself as SKK Medium dictionary version 8.1,
 May 24, 1995, rearranged for Plan 9 ktrans by Kenji Okamoto on February 17,
 2000.  Its header names its copyright holders and grants GPL version 2 or