feat: IME-aware chat input, message copy button, Git path scanning

- Fix IME composition issue: Enter during Chinese/Japanese/Korean input
  method composition no longer prematurely sends messages (assistant.js)
  Uses e.isComposing + keyCode 229 guard on keydown handler
- Add one-click copy button to chat message bubbles (both chat.js and
  assistant.js), with hover-reveal animation and checkmark feedback
- Add 'copy' icon to SVG icon library (Lucide style)
- Add CSS for msg-copy-btn in chat.css and assistant.css
- Implement scan_git_paths Rust command: scans common Git installation
  locations on Windows/macOS/Linux (Program Files, Scoop, Chocolatey,
  GitHub Desktop, VS Code, MSYS2, Homebrew, Xcode CLT, etc.)
- Register scan_git_paths in lib.rs, tauri-api.js, dev-api.js
- Add scan button + results UI in settings.js Git path section
- Add i18n keys: gitScan, gitScanning, gitScanEmpty, gitScanUse

src/pages/assistant.js

@@ -2431,10 +2431,10 @@ function renderMessages() {
           ? `<img class="ast-msg-img" src="${img.dataUrl}" alt="${escHtml(img.name)}" style="max-width:${Math.min(img.width || 300, 300)}px" loading="lazy"/>`
           : `<div class="ast-msg-img-loading" data-db-id="${img.dbId || ''}"><svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" width="24" height="24"><rect x="3" y="3" width="18" height="18" rx="2"/><circle cx="8.5" cy="8.5" r="1.5"/><polyline points="21 15 16 10 5 21"/></svg><span>${escHtml(img.name || t('assistant.image'))}</span></div>`
       ).join('')}</div>` : ''
-      return `<div class="ast-msg ast-msg-user" data-msg-idx="${idx}"><div class="ast-msg-bubble ast-msg-bubble-user">${imagesHtml}${textPart ? escHtml(textPart) : ''}</div></div>`
+      return `<div class="ast-msg ast-msg-user" data-msg-idx="${idx}"><div class="ast-msg-bubble ast-msg-bubble-user">${imagesHtml}${textPart ? escHtml(textPart) : ''}</div><div class="ast-msg-meta"><button class="msg-copy-btn" title="${t('common.copy')}">${icon('copy', 12)}</button></div></div>`
     } else if (m.role === 'assistant') {
       const toolHtml = renderToolBlocks(m.toolHistory)
-      return `<div class="ast-msg ast-msg-ai" data-msg-idx="${idx}">${toolHtml}<div class="ast-msg-bubble ast-msg-bubble-ai">${renderMarkdown(m.content)}</div></div>`
+      return `<div class="ast-msg ast-msg-ai" data-msg-idx="${idx}">${toolHtml}<div class="ast-msg-bubble ast-msg-bubble-ai">${renderMarkdown(m.content)}</div><div class="ast-msg-meta"><button class="msg-copy-btn" title="${t('common.copy')}">${icon('copy', 12)}</button></div></div>`
     }
     return ''
   }).join('')
@@ -4067,6 +4067,23 @@ export async function render() {
 
   // ── 事件绑定 ──
 
+  // 复制按钮（事件委托）
+  _messagesEl.addEventListener('click', (e) => {
+    const copyBtn = e.target.closest('.msg-copy-btn')
+    if (!copyBtn) return
+    e.stopPropagation()
+    const msgWrap = copyBtn.closest('.ast-msg')
+    const bubble = msgWrap?.querySelector('.ast-msg-bubble')
+    if (bubble) {
+      const text = bubble.innerText || bubble.textContent || ''
+      navigator.clipboard.writeText(text.trim()).then(() => {
+        copyBtn.classList.add('copied')
+        copyBtn.innerHTML = icon('check', 12)
+        setTimeout(() => { copyBtn.classList.remove('copied'); copyBtn.innerHTML = icon('copy', 12) }, 1500)
+      }).catch(() => {})
+    }
+  })
+
   // 右键调试菜单（事件委托）
   _messagesEl.addEventListener('contextmenu', (e) => {
     const msgEl = e.target.closest('[data-msg-idx]')
@@ -4084,9 +4101,9 @@ export async function render() {
     }
   })
 
-  // Enter 发送，Shift+Enter 换行
+  // Enter 发送，Shift+Enter 换行；IME 选词中不发送
   _textarea.addEventListener('keydown', (e) => {
-    if (e.key === 'Enter' && !e.shiftKey) {
+    if (e.key === 'Enter' && !e.shiftKey && !e.isComposing && e.keyCode !== 229) {
       e.preventDefault()
       if (!_textarea.value.trim() && _pendingImages.length === 0) return
       sendMessage(_textarea.value)

src/pages/chat.js

@@ -394,7 +394,7 @@ function bindEvents(page) {
   })
 
   _textarea.addEventListener('keydown', (e) => {
-    if (e.key === 'Enter' && !e.shiftKey) { e.preventDefault(); sendMessage() }
+    if (e.key === 'Enter' && !e.shiftKey && !e.isComposing && e.keyCode !== 229) { e.preventDefault(); sendMessage() }
     if (e.key === 'Escape') hideCmdPanel()
   })
 
@@ -536,7 +536,24 @@ function bindEvents(page) {
     _autoScrollEnabled = true
     scrollToBottom(true)
   })
-  _messagesEl.addEventListener('click', () => hideCmdPanel())
+  _messagesEl.addEventListener('click', (e) => {
+    const copyBtn = e.target.closest('.msg-copy-btn')
+    if (copyBtn) {
+      e.stopPropagation()
+      const msgWrap = copyBtn.closest('.msg')
+      const bubble = msgWrap?.querySelector('.msg-bubble')
+      if (bubble) {
+        const text = bubble.innerText || bubble.textContent || ''
+        navigator.clipboard.writeText(text.trim()).then(() => {
+          copyBtn.classList.add('copied')
+          copyBtn.innerHTML = svgIcon('check', 12)
+          setTimeout(() => { copyBtn.classList.remove('copied'); copyBtn.innerHTML = svgIcon('copy', 12) }, 1500)
+        }).catch(() => {})
+      }
+      return
+    }
+    hideCmdPanel()
+  })
 }
 
 async function loadModelOptions(showToast = false) {
@@ -1733,6 +1750,7 @@ function handleChatEvent(payload) {
           parts.push(`<span class="meta-sep">·</span><span class="msg-tokens">${tokenStr}</span>`)
         }
       }
+      parts.push(`<button class="msg-copy-btn" title="${t('common.copy')}">${svgIcon('copy', 12)}</button>`)
       meta.innerHTML = parts.join('')
       wrapper.appendChild(meta)
     }
@@ -2335,7 +2353,7 @@ function appendUserMessage(text, attachments = [], msgTime) {
 
   const meta = document.createElement('div')
   meta.className = 'msg-meta'
-  meta.innerHTML = `<span class="msg-time">${formatTime(msgTime || new Date())}</span>`
+  meta.innerHTML = `<span class="msg-time">${formatTime(msgTime || new Date())}</span><button class="msg-copy-btn" title="${t('common.copy')}">${svgIcon('copy', 12)}</button>`
 
   wrap.appendChild(bubble)
   wrap.appendChild(meta)
@@ -2362,7 +2380,7 @@ function appendAiMessage(text, msgTime, images, videos, audios, files, tools) {
 
   const meta = document.createElement('div')
   meta.className = 'msg-meta'
-  meta.innerHTML = `<span class="msg-time">${formatTime(msgTime || new Date())}</span>`
+  meta.innerHTML = `<span class="msg-time">${formatTime(msgTime || new Date())}</span><button class="msg-copy-btn" title="${t('common.copy')}">${svgIcon('copy', 12)}</button>`
 
   wrap.appendChild(bubble)
   wrap.appendChild(meta)

src/pages/settings.js

@@ -471,6 +471,13 @@ function bindEvents(page) {
         case 'reset-git-path':
           await handleResetGitPath(page)
           break
+        case 'scan-git-paths':
+          await handleScanGitPaths(page)
+          break
+        case 'use-scanned-git':
+          page.querySelector('[data-name="git-path"]').value = btn.dataset.gitPath || ''
+          await handleSaveGitPath(page)
+          break
         case 'bind-cli':
           await handleBindCli(page, btn.dataset.path)
           break
@@ -587,7 +594,9 @@ async function loadGitPath(page) {
           <input class="input" data-name="git-path" value="${escapeHtml(customValue)}" placeholder="${t('settings.gitPathPlaceholder')}" style="flex:1;min-width:200px">
           <button class="btn btn-primary btn-sm" data-action="save-git-path">${t('common.save')}</button>
           <button class="btn btn-secondary btn-sm" data-action="reset-git-path">${t('settings.resetDefault')}</button>
+          <button class="btn btn-secondary btn-sm" data-action="scan-git-paths">${t('settings.gitScan')}</button>
         </div>
+        <div id="git-scan-results"></div>
       </div>`
   } catch (e) {
     bar.innerHTML = `<div class="stat-card" style="padding:16px;color:var(--error)">${e}</div>`
@@ -613,6 +622,29 @@ async function handleSaveGitPath(page) {
   await loadGitPath(page)
 }
 
+async function handleScanGitPaths(page) {
+  const container = page.querySelector('#git-scan-results')
+  if (!container) return
+  container.innerHTML = `<div style="margin-top:10px;font-size:12px;color:var(--text-secondary)">${t('settings.gitScanning')}</div>`
+  try {
+    const results = await api.scanGitPaths()
+    if (!results || results.length === 0) {
+      container.innerHTML = `<div style="margin-top:10px;font-size:12px;color:var(--text-tertiary)">${t('settings.gitScanEmpty')}</div>`
+      return
+    }
+    container.innerHTML = `<div style="margin-top:10px;display:flex;flex-direction:column;gap:6px">${results.map(r =>
+      `<div style="display:flex;align-items:center;gap:8px;font-size:12px;padding:6px 8px;background:var(--bg-tertiary);border-radius:var(--radius-sm)">
+        <span style="flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap" title="${escapeHtml(r.path)}">${escapeHtml(r.path)}</span>
+        <span style="color:var(--text-tertiary);flex-shrink:0">${escapeHtml(r.version || '')}</span>
+        <span class="badge" style="font-size:10px;flex-shrink:0">${escapeHtml(r.source)}</span>
+        <button class="btn btn-primary btn-sm" style="padding:2px 8px;font-size:11px" data-action="use-scanned-git" data-git-path="${escapeHtml(r.path)}">${t('settings.gitScanUse')}</button>
+      </div>`
+    ).join('')}</div>`
+  } catch (e) {
+    container.innerHTML = `<div style="margin-top:10px;font-size:12px;color:var(--error)">${e}</div>`
+  }
+}
+
 async function handleResetGitPath(page) {
   const cfg = await api.readPanelConfig()
   delete cfg.gitPath