feat: 添加饮食文字AI识别功能与代码文档

- 饮食页面新增"文字AI识别"按钮，支持输入文字描述后自动识别卡路里
- 修复 database.py 中 time 模块导入冲突问题
- 新增 CODEMAPS.md 代码结构文档

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/vitals/web/app.py

@@ -5037,7 +5037,8 @@ def get_meal_page_html() -> str:
                 </select>
 
                 <label for="meal-description">食物描述</label>
-                <textarea id="meal-description" name="description" rows="3"></textarea>
+                <textarea id="meal-description" name="description" rows="3" placeholder="例如：一碗米饭、两个鸡蛋、一份青菜"></textarea>
+                <button type="button" id="textRecognizeBtn" onclick="recognizeFoodFromText()" style="margin-top:8px; background:#10b981;">文字AI识别</button>
 
                 <label for="meal-calories">卡路里（可选，留空自动估算）</label>
                 <input type="number" id="meal-calories" name="calories" min="0" inputmode="numeric">
@@ -5075,6 +5076,7 @@ def get_meal_page_html() -> str:
             // 重置识别状态
             document.getElementById('recognizeBtn').style.display = 'none';
             document.getElementById('recognizeStatus').style.display = 'none';
+            document.getElementById('textRecognizeBtn').disabled = false;
         }
         // ESC 键关闭 Modal
         document.addEventListener('keydown', (e) => {
@@ -5161,6 +5163,73 @@ def get_meal_page_html() -> str:
             }
         }
 
+        async function recognizeFoodFromText() {
+            const descriptionInput = document.getElementById('meal-description');
+            const statusDiv = document.getElementById('recognizeStatus');
+            const textRecognizeBtn = document.getElementById('textRecognizeBtn');
+
+            const text = descriptionInput.value.trim();
+            if (!text) {
+                alert('请先输入食物描述');
+                return;
+            }
+
+            // 显示识别中状态
+            statusDiv.style.display = 'block';
+            statusDiv.style.background = '#e3f2fd';
+            statusDiv.style.color = '#1976d2';
+            statusDiv.innerHTML = '🤖 正在识别食物，请稍候...';
+            textRecognizeBtn.disabled = true;
+
+            try {
+                const formData = new FormData();
+                formData.append('text', text);
+                formData.append('provider', 'qwen');
+
+                const res = await fetch('/api/meal/recognize', {
+                    method: 'POST',
+                    body: formData,
+                });
+
+                const result = await res.json();
+
+                if (res.ok && result.success) {
+                    // 显示成功状态
+                    statusDiv.style.background = '#e8f5e9';
+                    statusDiv.style.color = '#2e7d32';
+                    statusDiv.innerHTML = `✅ 识别成功！<br>食物：${result.description}<br>卡路里：${result.total_calories} 卡`;
+
+                    // 自动填充表单（更新描述为标准化的描述）
+                    const form = document.getElementById('addMealForm');
+                    if (result.description) {
+                        form.querySelector('[name="description"]').value = result.description;
+                    }
+                    form.querySelector('[name="calories"]').value = result.total_calories || '';
+                    if (result.total_protein) {
+                        form.querySelector('[name="protein"]').value = result.total_protein.toFixed(1);
+                    }
+                    if (result.total_carbs) {
+                        form.querySelector('[name="carbs"]').value = result.total_carbs.toFixed(1);
+                    }
+                    if (result.total_fat) {
+                        form.querySelector('[name="fat"]').value = result.total_fat.toFixed(1);
+                    }
+                } else {
+                    // 显示错误状态
+                    statusDiv.style.background = '#ffebee';
+                    statusDiv.style.color = '#c62828';
+                    statusDiv.innerHTML = `❌ 识别失败：${result.detail || '未知错误'}`;
+                }
+            } catch (error) {
+                // 显示错误状态
+                statusDiv.style.background = '#ffebee';
+                statusDiv.style.color = '#c62828';
+                statusDiv.innerHTML = `❌ 识别失败：${error.message}`;
+            } finally {
+                textRecognizeBtn.disabled = false;
+            }
+        }
+
         function formatPhotoUrl(path) {
             if (!path) return null;
             const marker = '/.vitals/photos/';