Narrow 聯繫 cross_strait flagging to contact-copy

[jserv]

The previous standalone "聯繫 → 聯絡" rule treated a word that the MoE concise dictionary records as valid zh-TW as a blanket cross-strait term, producing false positives on general prose such as "民間文化聯繫", "國際聯繫", and "保持聯繫".

Replace it with explicit compound rules covering the UI/customer-service phrases where 聯絡 is the idiomatic TW form: 聯繫我們, 聯繫方式, 聯繫資訊, 聯繫管道, 聯繫電話, 聯繫客服, 如需協助請聯繫.
聯繫歷史 → 通話記錄 is unchanged.

Add scanner regression test that locks both directions of the behavior: the new compounds fire exactly once on contact-copy spans, and ordinary prose containing 聯繫 stays silent.

Close #89

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Summary by cubic

Narrowed cross-strait flagging for 聯繫 to only contact-copy phrases, preventing false positives in general prose. Added tests to ensure contact CTAs are flagged once and do not lower editorial confidence.

• Bug Fixes
  • Replaced blanket rule with phrase rules: 聯繫我們, 聯繫方式, 聯繫資訊, 聯繫管道, 聯繫電話, 聯繫客服, 如需協助請聯繫.
  • Kept 聯繫歷史 → 通話記錄 unchanged.
  • Added scanner tests: each phrase flags once; ordinary prose with 聯繫 is ignored; matches keep editorial_confidence unset.

^{Written for commit b5432dd. Summary will update on new commits. Review in cubic}