fix(i18n): polish Traditional Chinese AI agent copy

[nrps9909]

Summary

• Polish 121 Traditional Chinese strings in the AI agent settings for natural Taiwan terminology and clearer UI copy.
• Correct dynamic task labels, verification states, allowlist guidance, model and plugin settings, session wording, and channel configuration text.
• Keep product terms such as Agent, Skill, Weixin, WeCom, DingTalk, and Feishu aligned with the English source and surrounding UI.
• Change only frontend/src/lang/modules/zh-Hant.ts; all 204 agent catalog leaves and interpolation placeholders remain aligned with English.

Each string was reviewed against en.ts and its relevant Vue or TypeScript call site.

Validation

• npm run build:dev — passed, 7,578 modules transformed
• npx prettier --check src/lang/modules/zh-Hant.ts — passed
• npx eslint src/lang/modules/zh-Hant.ts — passed
• TypeScript AST key and placeholder parity check — 204/204 leaves, no missing or extra keys, no placeholder mismatches
• git diff --check — passed
• npm run type-check — the current tree reports 9 errors in unchanged Vue files outside this locale change; none reference the modified translation module