Three settings were only half-wired:
- autoPickByLanguage was saved but never read anywhere: delete it.
- showUnstableTail had a checkbox and a setter, but nothing ever called
the setter, so the checkbox did nothing: apply it in applyAppearance
and re-render from the cached text instead of blanking the caption.
- the language dropdown was hard-coded to auto/zh/en/ja while the registry
declares up to 16 languages per model: build it from the selected
model's own language list, with an ISO-code to display-name mapping
(plus a unit test covering every code in the registry). The caption
window's language pill now follows the setting too, instead of keeping
whatever it showed at startup.
windowPos is not dead -- it stores the dragged window position -- so it stays.
三个「半死」设置：autoPickByLanguage 存了但从没被读取，直接删掉；showUnstableTail
有复选框也有 setter，但从来没人调用 setter（复选框点了没用），改为在 applyAppearance
里生效并用缓存文本重画；「识别语言」下拉原来硬编码 自动/中/英/日，而注册表里每个模型
声明了最多 16 种语言，改为按所选模型的语言动态生成，并补 ISO 码→显示名映射与单元测试。
字幕窗的语言标签也跟着设置走了（原来只在启动时读一次）。windowPos 不是死设置（它存的
是拖动后的位置），保留。
These were command-line only. Add them to the settings dialog so the whole
feature set is reachable without arguments: stream mode, window limit,
segment limit, prefix-rollback token count, cold-start chunk count, max
tokens per step, thread count, verbose logging and the model directory. The
streaming group is grouped and greyed out for streaming-ONNX models, which
only use the commit granularity. The backend fingerprint now includes them,
so changing one restarts the recogniser; appearance changes still apply live.
Also add a test-only --settings-tab so a specific page can be screenshotted.
设置「高级」页补上原来只有命令行才有的选项：流式策略/滑窗上限/单段最长/前缀回滚
token 数/冷启动 chunk 数/单段最多生成 token/线程数/详细日志/模型目录。流式那一组
单独成组，选了流式 ONNX 模型时置灰（它们只用「更新粒度」）。这些值纳入「后端指纹」，
改动会重启识别后端；外观类改动仍然即时生效。另加测试用 --settings-tab 以便给单个
页签截图。
The README still listed the settings UI as "todo" and its quick start told
users to download models into the working directory; phase 3 still described
the caption window's close button as "quit" and used the wrong binary name.
Bring the docs up to date and fill the gaps: a GUI guide (first run, settings
tabs, tray, download, verify), a full CLI option reference marking the
test-only flags, a troubleshooting page, the model registry's size/sha256
fields plus a licence/size table, the RTF measurement caveat (llama-cli 0.19
vs the in-process 0.56), and a note that the streaming-ONNX backend has its
own code path. phase0/phase1 experiment docs are marked as historical.
文档与现状对齐：README 的 Phase 4 从「待做」改为完成、快速开始不再让人把模型下到当前
目录；phase3 的 ✕ 说明改为「隐藏到托盘」、用法改用 live-caption；新增 GUI/CLI/排错三份
文档；asr-backends 补上注册表的 size/sha256 字段与模型许可/体积表；phase0 补上 RTF 口径
说明（llama-cli 的 0.19 与程序内的 0.56）；phase2 补上「流式 ONNX 走另一条分支」的说明。
blumia