refactor: reorganize directory structure into src/

Move all source code directories into src/ for cleaner project structure:
- pages/, components/, utils/, config/, providers/, types/, lib/, assets/, entrypoints/ → src/
- Use WXT srcDir config to resolve @/ alias to src/
- Update tsconfig, vitest, eslint, tailwind configs
- Remove scattered README.md files from subdirectories
- Update documentation (AGENTS.md, CODING_STANDARDS.md, README.md)
- Fix pre-existing lint error in RouterProvider.tsx

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/pages/QrCode/contexts/QrCodeContext.ts

@@ -0,0 +1,35 @@
+import type { Dispatch, SetStateAction } from 'react'; // 💡 1. 显式解构导入类型，彻底掐灭 TS2304 报错
+import { createContext, useContext } from 'react';
+import type { QrCodeGeneratorState, QrCodeMode, QrCodeParserState } from '../types';
+
+export interface QrCodeContextValue {
+  // 核心主视图路由模式切换卡
+  mode: QrCodeMode;
+  setMode: (mode: QrCodeMode) => void;
+
+  // 1. 流式生成器终端状态机驱动
+  generatorState: QrCodeGeneratorState;
+  setTextToEncode: (text: string) => void;
+  // 💡 架构纯净化：物理剔除暴露给外部的命令式 generateQrCode 算子。
+  // 外部面板只需 setTextToEncode 驱动源文本更新，生成动作由内部流式管线全自动自发自愈完成！
+  downloadQrCode: () => void;
+  copyQrCode: () => Promise<void>;
+
+  // 2. 活态反向解析器终端状态机驱动
+  parserState: QrCodeParserState;
+  setParserState: Dispatch<SetStateAction<QrCodeParserState>>; // 💡 规整为纯净的直接类型使用
+  parseQrCode: (file: File) => Promise<void>;
+  handleFileChange: (file: File) => void;
+  handleClearFile: () => void;
+}
+
+export const QrCodeContext = createContext<QrCodeContextValue | null>(null);
+
+export function useQrCodeContext() {
+  const context = useContext(QrCodeContext);
+  if (!context) {
+    // 边界鲁棒性防护大闸
+    throw new Error('useQrCodeContext must be used within a valid QrCodeProvider container');
+  }
+  return context;
+}