Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver

- zephyr/module.yml with dts_root for dt-bindings
- Kconfig: STENO_ENGINE, dict selection (Plover/Lapwing/test),
  MPHF toggle, Unicode modes, history size, multi-stroke timeout
- DTS behavior binding (one_param, steno key index)
- behavior_steno.c: chord accumulation, all-up detection,
  multi-stroke buffering with timeout, star undo, formatter pipeline,
  3-way dict dispatch (split/MPHF/simple trie)
- dict_embed.S: .incbin from generated header path
- steno_keys.h: 23-key layout, bit positions matching compiler

dicts/test.json

@@ -0,0 +1,48 @@
+{
+  "S": "is",
+  "T": "it",
+  "-T": "the",
+  "K": "can",
+  "W": "with",
+  "H": "had",
+  "R": "are",
+  "A": "a",
+  "AOEU": "I",
+  "TKPW": "go",
+  "HRAO": "hello",
+  "WORBGD": "world",
+  "KAT": "cat",
+  "TKOG": "dog",
+  "HOUS": "house",
+  "TPEUR": "fire",
+  "WAURT": "water",
+  "TPOOD": "food",
+  "PWO*BG": "book",
+  "KO": "co",
+  "KO/PHAOURD": "computer",
+  "KO/PHAOURDZ": "computers",
+  "TEFT": "test",
+  "TEFTD": "tested",
+  "TEFTG": "testing",
+  "STE/TPHO": "steno",
+  "STE/TPHOG": "stenography",
+  "KPA": "{}{-|}",
+  "S-P": "{^ ^}",
+  "TP-PL": "{.}",
+  "KW-BG": "{,}",
+  "H-F": "{?}",
+  "SKHRAPL": "{!}",
+  "*": "{*}",
+  "TPHO": "no",
+  "KWRA": "yes",
+  "THA": "that",
+  "PWUT": "but",
+  "TPHOT": "not",
+  "SREU": "have",
+  "WHA": "what",
+  "HEU": "he",
+  "SHEU": "she",
+  "THE": "they",
+  "WE": "we",
+  "KWREU": "I"
+}