优化: 前端扫描文案 i18n + parseStack 抽公共 + alert/confirm 换组件

- 扫描/目录状态文案走 $t（Projects/ProjectDetail，zh-CN+en 同步）
- parseStack 抽公共到 src/utils/project.ts（删两份本地实现）
- 8 处原生 alert/confirm 全换（confirm→ConfirmDialog / alert→Arco Message），控制流语义不变

Sprint 20 审查 ⑥⑦⑧。vue-tsc 0 error，验证 safe 0 issue

src/i18n/en/projectDetail.ts

@@ -48,6 +48,13 @@ export default {
     relocateDir: 'Relocate',
     bindDir: 'Bind Directory',
     dirStatusLabel: 'Directory Status',
+    dirChecking: 'Checking…',
+    dirExists: '✓ Directory exists',
+    dirMissing: '⚠ Directory moved, recommend relocate',
+    dirConflict: 'This directory is already bound to project "{name}"',
+    relocateConfirmRelocate: 'Relocate project directory to:\n{dir}\n\nTech stack will be re-detected. Confirm?',
+    relocateConfirmBind: 'Bind project directory to:\n{dir}\n\nTech stack will be re-detected. Confirm?',
+    relocateFailed: 'Relocate failed: {msg}',
     // Tech stack
     techStackLabel: 'Tech Stack',
   },

src/i18n/en/projects.ts

@@ -26,9 +26,16 @@ export default {
     confirmPurge: 'Permanently delete project "{name}"? Tasks/branches/releases will be physically deleted and cannot be recovered!',
     // New fields
     codeDirLabel: 'Code Directory',
+    codeDirOptionalHint: '(optional, auto-detects tech stack once bound)',
     codeDirPlaceholder: 'Click the button on the right to select project directory',
     selectDir: 'Select Directory',
     clearDir: 'Clear',
+    // AI scan
+    aiScanning: 'AI scanning…',
+    aiScanFill: '🤖 AI scan & autofill',
+    aiScanNoDesc: 'AI could not generate a description, please fill manually',
+    aiScanFailed: 'AI scan failed',
+    dirConflict: 'This directory is already bound to project "{name}"',
     // Status labels (PROJECT_STATUS_LABELS values in constants/project.ts use these keys)
     status: {
       planning: '📐 Planning',

src/i18n/zh-CN/projectDetail.ts

@@ -48,6 +48,13 @@ export default {
     relocateDir: '重定位',
     bindDir: '绑定目录',
     dirStatusLabel: '目录状态',
+    dirChecking: '检测中…',
+    dirExists: '✓ 目录存在',
+    dirMissing: '⚠ 目录已移走，建议重定位',
+    dirConflict: '该目录已被项目「{name}」绑定',
+    relocateConfirmRelocate: '将项目目录重定位到:\n{dir}\n\n技术栈将重新探测。确认?',
+    relocateConfirmBind: '将项目目录绑定到:\n{dir}\n\n技术栈将重新探测。确认?',
+    relocateFailed: '重定位失败: {msg}',
     // 技术栈
     techStackLabel: '技术栈',
   },

src/i18n/zh-CN/projects.ts

@@ -11,10 +11,17 @@ export default {
     descLabel: '项目描述',
     descPlaceholder: '简要描述项目目标',
     codeDirLabel: '代码目录',
+    codeDirOptionalHint: '（可选，绑定后自动识别技术栈）',
     codeDirPlaceholder: '点击右侧选择项目所在目录',
     selectDir: '选择目录',
     clearDir: '清除',
     confirmCreate: '确认创建',
+    // AI 扫描
+    aiScanning: 'AI 扫描中…',
+    aiScanFill: '🤖 AI 扫描填信息',
+    aiScanNoDesc: 'AI 未能生成描述，可手动填写',
+    aiScanFailed: 'AI 扫描失败',
+    dirConflict: '该目录已被项目「{name}」绑定',
     // 回收站模态框
     trashTitle: '🗑 回收站',
     trashEmpty: '回收站为空',