docs: move localized docs into docs folder

- keep the English README at the repository root
- move localized README files and screenshots into docs
- update README and AGENTS references to the new docs paths

Author: clhuang224

AGENTS.md

@@ -17,8 +17,8 @@
 - Other files in `assets/js/*.js` should keep a focused responsibility instead of moving unrelated logic back into `app.js`.
 - `assets/js/locales/*.js` contains UI translations; any user-facing copy change should be updated across all locales.
 - `README.md` is the primary English README.
-- `README.zh-TW.md` and `README.ja.md` are localized README files and should be updated alongside the English README when needed.
-- `demo.png`, `demo.zh-TW.png`, and `demo.ja.png` are localized screenshots and should be updated together when the UI changes in a way that affects the documentation images.
+- `docs/README.zh-TW.md` and `docs/README.ja.md` are localized README files and should be updated alongside the English README when needed.
+- `docs/demo.png`, `docs/demo.zh-TW.png`, and `docs/demo.ja.png` are localized screenshots and should be updated together when the UI changes in a way that affects the documentation images.
 
 ## General Working Rules
 
@@ -67,12 +67,12 @@
 - English is the source language for project documentation.
 - When README content changes, review and update:
   - `README.md`
-  - `README.zh-TW.md`
-  - `README.ja.md`
+  - `docs/README.zh-TW.md`
+  - `docs/README.ja.md`
 - When screenshots become outdated due to UI changes, update:
-  - `demo.png`
-  - `demo.zh-TW.png`
-  - `demo.ja.png`
+  - `docs/demo.png`
+  - `docs/demo.zh-TW.png`
+  - `docs/demo.ja.png`
 - Localized README files and screenshots should stay meaningfully aligned with the English source.
 
 ## CSS / UI Style Guide

README.md

@@ -1,6 +1,6 @@
 # PrePrompt
 
-[English](./README.md) | [繁體中文](./README.zh-TW.md) | [日本語](./README.ja.md)
+[English](./README.md) | [繁體中文](./docs/README.zh-TW.md) | [日本語](./docs/README.ja.md)
 
 Replace sensitive details before sending text to an LLM.
 
@@ -16,7 +16,7 @@ If you want to test locally, serve this folder with any simple static server and
 
 ## Screenshot
 
-![demo](./demo.png)
+![demo](./docs/demo.png)
 
 ## Features
 
@@ -34,10 +34,13 @@ If you want to test locally, serve this folder with any simple static server and
 ```text
 .
 ├── index.html
-├── demo.png
 ├── README.md
-├── README.zh-TW.md
-├── README.ja.md
+├── docs
+│   ├── README.zh-TW.md
+│   ├── README.ja.md
+│   ├── demo.png
+│   ├── demo.zh-TW.png
+│   └── demo.ja.png
 └── assets
     ├── favicon.png
     ├── css

README.ja.md docs/README.ja.mdREADME.ja.md renamed to docs/README.ja.md

@@ -1,6 +1,6 @@
 # PrePrompt
 
-[English](./README.md) | [繁體中文](./README.zh-TW.md) | [日本語](./README.ja.md)
+[English](../README.md) | [繁體中文](./README.zh-TW.md) | [日本語](./README.ja.md)
 
 LLM に文章を貼り付ける前に、PrePrompt で機密情報を置き換えます。
 
@@ -34,10 +34,13 @@ PrePrompt はブラウザで動く小さなツールです。単なる文字置
 ```text
 .
 ├── index.html
-├── demo.png
 ├── README.md
-├── README.zh-TW.md
-├── README.ja.md
+├── docs
+│   ├── README.zh-TW.md
+│   ├── README.ja.md
+│   ├── demo.png
+│   ├── demo.zh-TW.png
+│   └── demo.ja.png
 └── assets
     ├── favicon.png
     ├── css

README.zh-TW.md docs/README.zh-TW.mdREADME.zh-TW.md renamed to docs/README.zh-TW.md

@@ -1,6 +1,6 @@
 # PrePrompt
 
-[English](./README.md) | [繁體中文](./README.zh-TW.md) | [日本語](./README.ja.md)
+[English](../README.md) | [繁體中文](./README.zh-TW.md) | [日本語](./README.ja.md)
 
 將文字貼進 LLM 前，用 PrePrompt 替換敏感資訊。
 
@@ -34,10 +34,13 @@ PrePrompt 是一個在瀏覽器中執行的小工具，重點不只是文字取
 ```text
 .
 ├── index.html
-├── demo.png
 ├── README.md
-├── README.zh-TW.md
-├── README.ja.md
+├── docs
+│   ├── README.zh-TW.md
+│   ├── README.ja.md
+│   ├── demo.png
+│   ├── demo.zh-TW.png
+│   └── demo.ja.png
 └── assets
     ├── favicon.png
     ├── css