refactor(preamble): carve CJK-escaping manual to on-demand doc

The AskUserQuestion format block is inlined into every interactive skill (~33).
It carried the full multi-paragraph non-ASCII/CJK escaping manual inline, but
that rationale only matters when a question contains CJK text and the operative
rule already lives in the always-loaded self-check. Moved the justification to
docs/askuserquestion-cjk.md (read on demand); kept the rule + a pointer.

Corpus: Claude-host SKILL.md total 3,087,499 -> 3,057,975 B (-29,524 B, ~900 B
x ~33 skills). Layer 0 still passes — the core decision-brief format stays
always-loaded; only the rare CJK rationale moved. Atomic with the all-host
regen (skill-docs.yml freshness gate). VERSION + package.json -> 1.58.0.0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/askuserquestion-cjk.md

@@ -0,0 +1,29 @@
+# AskUserQuestion — non-ASCII / CJK characters
+
+Read this on demand when an AskUserQuestion contains Chinese (繁體/簡體),
+Japanese, Korean, or other non-ASCII text. The operative rule is in the
+always-loaded AskUserQuestion self-check ("Non-ASCII characters written directly,
+NOT \u-escaped"); this doc is the full justification.
+
+## The rule
+
+When any string field (question, option label, option description) contains
+non-ASCII text, emit the literal UTF-8 characters in the JSON string. **Never
+escape them as `\uXXXX`.**
+
+Claude Code's tool parameter pipe is UTF-8 native and passes characters through
+unchanged. Only JSON-mandatory escapes remain allowed: `\n`, `\t`, `\"`, `\\`.
+
+## Why escaping fails
+
+Manually escaping requires recalling each codepoint from training, which is
+unreliable for long CJK strings — the model regularly emits the wrong codepoint.
+Example: writing `㄃` thinking it is 管 (U+7BA1), but `㄃` is actually ㄃,
+so the user sees `管理工具` rendered as `㄃3用箱`.
+
+The trigger is long, multi-line questions with hundreds of CJK characters: that
+is exactly when reflexive escaping kicks in and exactly when miscoding is most
+damaging. Long ≠ escape. Keep characters literal.
+
+- Wrong: `"question": "請選擇\uXXXX\uXXXX\uXXXX\uXXXX"`
+- Right: `"question": "請選擇管理工具"`