zh-CN translations are incomplete — many keys missing across 6 files

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The Chinese (zh-CN) translation files are missing many keys. A PR branch (`zh-CN-complete`) has completed translations for 6 files with ~400 new/changed entries, but the changes have not been merged.

## What's missing

Each of these files has missing keys. For example:

**zh-CN/chat.json** is missing keys like:
```
genInfo/tokensPerSecond
genInfo/predictedTokensCount
genInfo/timeToFirstTokenSec
genInfo/stopReason
genInfo/stopReason.userStopped
genInfo/stopReason.eosFound
genInfo/stopReason.stopStringFound
genInfo/stopReason.maxPredictedTokensReached
genInfo/stopReason.contextLengthReached
actions/clearLastUsedModel
actions/clearLastUsedModel/error
messageBlocks/expandBlockTooltip
messageBlocks/collapseBlockTooltip
```

**zh-CN/config.json** is missing keys like:
```
llm/load/numParallelSessions/title
llm/load/numParallelSessions/subTitle
llm/load/useUnifiedKvCache/title
llm/load/useUnifiedKvCache/subTitle
presets/saveChanges/manual
presets/saveChanges/manual/hold/0
presets/saveChanges/manual/hold/1
presets/saveChanges/saveAll/hold/0
presets/saveChanges/saveAll/hold/1
```

**zh-CN/developer.json** is missing keys like:
```
endpoints/lmStudioRest/segmentedLabel
serverOptions/allowMcp/title
serverOptions/allowMcp/hint
serverOptions/allowMcp/mode/off
serverOptions/allowMcp/mode/off/hint
serverOptions/allowMcp/mode/remote
serverOptions/allowMcp/mode/remote/hint
```

And similar gaps in `zh-CN/models.json`, `zh-CN/settings.json`, `zh-CN/shared.json`.

## What good translations look like

For the missing keys, here are examples of how they should be translated:

In `zh-CN/chat.json`:
```json
"genInfo/tokensPerSecond": "生成速度",
"genInfo/predictedTokensCount": "预测 token 数",
"genInfo/timeToFirstTokenSec": "首 token 生成时间",
"genInfo/stopReason": "停止原因：{{reason}}",
"genInfo/stopReason.userStopped": "用户停止",
"genInfo/stopReason.eosFound": "遇到结束符",
"genInfo/stopReason.stopStringFound": "遇到停止字符串",
"messageBlocks/expandBlockTooltip": "展开消息块",
"messageBlocks/collapseBlockTooltip": "收起消息块",
```

In `zh-CN/config.json`:
```json
"llm/load/numParallelSessions/title": "并行会话数",
"llm/load/numParallelSessions/subTitle": "设置可与模型同时交互的会话数量",
"llm/load/useUnifiedKvCache/title": "统一 KV 缓存",
"presets/saveChanges/manual": "手动保存",
```

## How to verify

1. Check out the `zh-CN-complete` branch
2. Compare each of the 6 files against the current `main`:
- `zh-CN/chat.json` — 285 lines (PR) vs 228 lines (main)
- `zh-CN/config.json` — 1504 lines changed
- `zh-CN/developer.json` — 406 lines changed
- `zh-CN/models.json` — 236 lines changed
- `zh-CN/settings.json` — 394 lines changed
- `zh-CN/shared.json` — 41 lines changed
3. Review the translations and merge what looks good

## Files affected

- zh-CN/chat.json
- zh-CN/config.json
- zh-CN/developer.json
- zh-CN/models.json
- zh-CN/settings.json
- zh-CN/shared.json

Start by checking out the `zh-CN-complete` branch and comparing its six listed files with `main`: `chat.json`, `config.json`, `developer.json`, `models.json`, `settings.json`, and `shared.json`. Review the roughly 400 changed or new entries for accurate, consistent Chinese translations and confirm that the missing keys are covered in all six files. Done means the reviewed translations are merged into the current branch.

Written by the indexing model from the issue text.