[Apageoflove]

上一条 PR（#96）把 @ 前面的那个字按书写系统来判：拉丁、希腊、西里尔这些用空格分词的文字，它挡在 @ 前面就说明那是一个地址，点不到人；中文、日文、韩文紧贴着 @ 写词，所以它们不算。评审里指出还有两类同样紧贴着 @ 写的字没算进去：全角输入法打出来的全角字母和数字，以及泰语、老挝语、高棉语、缅甸文——这四种文字也都不用空格分词。
这一版把这两类加进「不算地址」的那一组：全角输入法写出来的全角字母和数字紧贴着 @ 时，现在还能点到人；那四种文字紧贴着 @ 时也还能点到人。而一个用空格分词的文字（带重音的拉丁字母、希腊字母、西里尔字母）接在 @ 前面时，仍然点不到人，它是一个地址。全角与半角形式是 U+FF00 到 U+FFEF 这一段。
README 也补了一段：0.7.16 那次是改了规则（一个用空格分词的文字接在 @ 前面，在 0.7.15 会点到人、0.7.16 起不会），上一版只改写了 0.7.13 那一段，读者看不出规则变过，现在补一段把这件事记下来。
新加的用例在未改的上游代码上是红的，在这版上是绿的；插件自带套件 344 条全过，上游 npm run check 两半也过。
这一版只补齐「哪些文字紧贴着 @ 写词」的判断，不改 @ 前面是别的文字时的行为；名字后面紧跟中文的边界维持上游原有的语义，没有动。这之外还有没有别的紧贴着写词的文字，需要确认之后再补。

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[MyPrototypeWhat]

Thanks for the follow-up on #96. Approving.

The change is small, and so is the risk:

• Thai, Lao, Khmer and Myanmar now join the scripts that write right up against the @, so ขอบคุณ@alice reaches Alice.
• Latin, Greek and Cyrillic in front of the @ still make an address (josé@alice, mail@alice.com).
• Full-width letters and digits typed with an IME (ＯＫ@alice, 第２@alice) now reach the member too.
• The \uFF00-\uFFEF range also covers full-width punctuation, which is harmless: isAddressChar only applies to word characters, so punctuation before the @ was never treated as part of an address.
• Half-width katakana (ｶﾅ@alice) was already covered under Katakana and still works.

Verified

• I spot-checked a few extra cases locally. ，@alice and 、@alice mention, and abc@alice doesn't.
• ｍａｉｌ@alice.com now counts as a mention. That's fine with me, since nobody types a real address in full-width.
• CI passes, and npm run check passes locally.
• Plugin tests pass at 341/344, including the new test. The 3 failures are the emoji picker tests, which fail on main in my environment too.
• The version is 0.7.19 in package.json, plugin.json, serverInfo in mcp.mjs, and the README.

Optional

• The full-width at sign ＠ (U+FF20) isn't recognized as a mention, because the scan only looks for the ASCII @. That was true before this PR too. If full-width IME users matter here, a later PR could handle it.
• The new README section sits between 0.7.12 and 0.7.13. Moving it next to the other recent entries would make it easier to find.

Heads-up: this PR touches the same version lines as #97 (0.7.17) and #98 (0.7.18). Since 0.7.19 comes after both, it should merge last of the three and will need a small rebase on the version lines and the README changelog.