docs(semantics): record iterative retraining study

Co-authored-by: Rocky <hkgood@users.noreply.github.com>

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - **Clipboard intent precision**: specialize the local task and complaint models, add conservative language thresholds, and suppress complaint-only text from task routing unless it contains an explicit assignment. / **剪贴板意图精度**：专项优化本地任务与投诉模型，加入保守的分语言阈值，并在没有明确委派时阻止纯投诉文本进入任务路由。
 - **Precision-first semantic routing**: add traceable multi-model consensus labels, local joint intent verifiers, confidence-margin abstention, layered source-isolated evaluation, and privacy-safe shadow disagreement counters while retaining current models until every acceptance gate passes. / **精度优先语义路由**：新增可追溯多模型共识银标、本地联合意图验证器、置信度与差值拒识、按来源隔离的分层评估及隐私安全的影子分歧计数；所有验收门槛通过前继续保留当前模型。
+- **Iterative semantic research**: add reproducible twenty-round weakly supervised model selection, high-confidence self-training consensus, per-intent fine-tuning, explicit-evidence experiments, frozen-overlap gates, and macOS replay manifests; retain deployed models when every candidate underperforms release baselines. / **迭代语义研究**：新增可复现的二十轮弱监督模型选择、高置信自训练共识、分意图微调、显式证据实验、冻结集重叠门禁及 macOS 重放清单；所有候选低于发布基线时继续保留现有部署模型。
 - **Card depth**: add a faint directional long shadow to card surfaces throughout the iOS app in both light and dark appearances. / **卡片层次**：为 iOS App 内的卡片界面统一加入淡雅的定向长投影，并适配浅色与深色外观。
 - **Neutral dialog actions**: use adaptive black or white styling for system alerts, confirmation dialogs, and modal actions instead of inheriting the green brand accent. / **中性弹窗操作色**：系统警告、确认弹窗及模态操作改用自适应黑色或白色，不再继承绿色品牌强调色。
 - **Monthly usage calendar**: replace the seven-day Home and Mac Dashboard chart with a full current-month calendar whose date-circle opacity reflects each day's dictation characters, placing the Home calendar between its four metrics and Personal Dictionary. / **月度用量日历**：以完整的当月日历替换首页与 Mac 总览的近七天图表，并通过日期圆形背景透明度表示每天的听写字数；首页日历位于四项统计指标与个性词库之间。