math_script_insensitive: Unicode coverage audit — combining macron (X̄), Greek subscripts U+1D66..U+1D6A, U+2094 schwa (cross-repo with ooxml-swift)

[kiki830621]

Problem

From verify of #115 (DA P2 #2 + Codex P2 #3):
「lib 的 mathScriptVariantMap 是手動列舉式，漏掉：(a) combining macron U+0304 — issue body 明確列 X̄ = X + ̄ 為典型 anchor pattern；(b) Greek subscripts U+1D66..U+1D6A (ᵦᵧᵨᵩᵪ) — 統計／物理論文 Σᵦ、Πᵧ 等常用標記；(c) U+2094 ₔ（subscript schwa） — 罕見但若驗收標準是『完整 U+2090..U+209C』，這裡還不完整。」
— Source: team:devils-advocate (P2) + codex (P2/P3)
Verify report: #115 (comment)

Type

enhancement / cross-repo (ooxml-swift + che-word-mcp)

Affected location

• packages/ooxml-swift/Sources/OOXMLSwift/Models/InsertLocation.swift:75-90 (mathScriptVariantMap)
• Sources/CheWordMCP/Server.swift schema descriptions (跟 issue P3 配合)

Strategy

1. NFD normalization for combining marks：

Combining macron U+0304 必須先 Unicode NFD decompose 再 strip。X̄ 在 NFC 是 X + ̄（2 char），NFD 同樣。strip combining marks 後得到 X。建議：

extension String {
    var stripCombiningMarks: String {
        let nfd = self.decomposedStringWithCanonicalMapping  // NSString.precomposedStringWithCanonicalMapping
        return String(nfd.unicodeScalars.filter { !$0.properties.isDiacritic })
    }
}

// In matcher:
let canonicalNeedle = mapToAscii(needle.stripCombiningMarks)
let canonicalHaystack = mapToAscii(haystack.stripCombiningMarks)

2. Greek subscript range U+1D66..U+1D6A：

Code	Char	ASCII map
U+1D66	ᵦ	β
U+1D67	ᵧ	γ
U+1D68	ᵨ	ρ
U+1D69	ᵩ	φ
U+1D6A	ᵪ	χ

加進 mathScriptVariantMap。

3. U+2094 ₔ subscript schwa：

加 (0x2094, "ə")。

Test

• H̄ (combining macron) flag on → match H
• X̄ + Ȳ flag on → match needle X + Y
• Σᵦ flag on → match Σβ
• aₔb flag on → match aəb
• 跨 case：X̄ 與 X flag on 雙向 match

Related

• Add math-script match options to insertion anchors #115 (PR), P3 enhancement: H₀ Unicode subscript anchors don't match flatten output (post-#85 follow-up) #90 (root issue, body 明列 X̄)
• ooxml-swift#38 (cross-repo)

[kiki830621]

已在 ooxml-swift commit d71e6c3 完整解決（X̄ combining macron NFD strip + Greek subscripts U+1D66..U+1D6A + U+2094 schwa），釋出於 v0.22.0。che-word-mcp PR #115 Package.swift 已 bump 到 from: "0.22.0"，merge 後使用者直接拿到。