match_options: reject typo'd / unknown keys instead of silent fallback (additionalProperties: false policy)

[kiki830621]

Problem

From verify of #115 (Logic L1):
「Typo'd keys silently fall back：{"match_options": {"math_script_insensitve": true}}（缺 i）會被 silently 忽略而非 reject。Schema 缺 additionalProperties: false。」
— Source: team:logic L1 (P3)
Verify report: #115 (comment)

Type

policy decision / strict mode

Scope

不只 match_options — Server.swift 整個 schema surface 都沒有 additionalProperties: false。LLM caller 拼錯 key 會 silently fall back，very common footgun。

Strategy

Option 1（針對 match_options）：在 parseAnchorLookupOptions 加 unknown key check：

let knownKeys: Set<String> = ["math_script_insensitive"]
if let .object(opts) = rawOptions {
    let unknown = opts.keys.filter { !knownKeys.contains($0) }
    if !unknown.isEmpty {
        return (.exact, "Error: \(tool): unknown match_options keys: \(unknown.joined(separator: ", "))")
    }
}

Option 2（policy-level）：跨整個 Server.swift schema 系統加 additionalProperties: false，並寫 grep test 守護新工具。

Option 1 是 narrow fix；Option 2 影響面大、可能 break 既有 caller。建議：先 Option 1 covering match_options + critical args（doc_id/comment_id/paragraph_index 等），policy-level 改動拆獨立 SDD/PR。

Test

• match_options.math_script_insensitve (typo) → reject with structured error
• match_options.foo (unknown key) → reject

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
• Cross-cutting: similar concerns in PR Add comment review workflow helpers #112 (add_comment_reply / reply_to_comment: align schema-level required across alias names #133 alias schema asymmetry)