feat(ai-outfit): auto-append output requirements to prompt (§19.6)

- core/ai_outfit: OUTPUT_REQUIREMENTS constant + build_output_requirements();
  render_prompt(template, task, resolution=None) appends the block when a
  resolution is given; generate_outfit_image passes the current resolution.
- ai_outfit_panel: inline preview now uses render_prompt/build_output_requirements
  with the selected resolution and refreshes when the resolution combo changes,
  so the preview equals what is actually sent.
- tests: +3 cases (tail with resolution, none without, helper empty/filled);
  updated the success test for the appended tail. Full suite (12 files) green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/widgets/ai_outfit_panel.py

@@ -258,6 +258,7 @@ class AiOutfitPanel(QWidget):
         self._retry_count.setRange(0, 10)
         self._resolution = QComboBox()
         self._resolution.addItems(_RESOLUTIONS)
+        self._resolution.currentIndexChanged.connect(self._refresh_preview)
         self._quality = QComboBox()
         self._quality.addItems(_QUALITIES)
 
@@ -472,17 +473,19 @@ class AiOutfitPanel(QWidget):
     def _refresh_preview(self):
         if not hasattr(self, "_preview_view"):
             return
+        from core.ai_outfit import build_output_requirements, render_prompt
         template = self._prompt_edit.toPlainText()
         self._preview_warn.setVisible("{title}" not in template)
         if "{title}" not in template:
             self._preview_warn.setText("⚠ 话术缺少 {title} 占位符")
+        # Mirror what actually gets sent: append the output-requirements block
+        # for the currently selected resolution (docs/11 §7.1).
+        resolution = self._resolution.currentText() if hasattr(self, "_resolution") else None
         task = self._sample_combo.currentData() if hasattr(self, "_sample_combo") else None
         if task is None:
-            self._preview_view.setPlainText(template)
+            self._preview_view.setPlainText(template + build_output_requirements(resolution))
         else:
-            rendered = template.replace("{title}", task.title).replace(
-                "{product_id}", task.product_id)
-            self._preview_view.setPlainText(rendered)
+            self._preview_view.setPlainText(render_prompt(template, task, resolution))
 
     # -- run control ----------------------------------------------------
 

src/core/ai_outfit.py

@@ -25,10 +25,34 @@ QUALITY_PRESETS = {
 MAX_JPG_BYTES = 2 * 1024 * 1024
 _INVALID_FILENAME_CHARS = re.compile(r'[<>:"/\\|?*\x00-\x1f]')
 
+# Auto-appended to every prompt (ported from 标题生成产品图工具; docs/11 §7.1).
+# Only 参考解析度 is dynamic (the chosen resolution); the rest is fixed.
+OUTPUT_REQUIREMENTS = (
+    "\n\n批量生成输出要求："
+    "\n- 参考解析度：{resolution}"
+    "\n- 固定 1:1 正方形主图"
+    "\n- 必须结合商品标题与参考商品图片"
+    "\n- 服装本身、版型、颜色与图案不可跑版"
+)
 
-def render_prompt(template, task):
-    """Render an outfit prompt for one task."""
-    return str(template).replace("{title}", task.title).replace("{product_id}", task.product_id)
+
+def build_output_requirements(resolution):
+    """Return the auto-appended output-requirements block (empty if no resolution)."""
+    if not resolution:
+        return ""
+    return OUTPUT_REQUIREMENTS.format(resolution=resolution)
+
+
+def render_prompt(template, task, resolution=None):
+    """Render the final prompt for one task.
+
+    Replaces {title}/{product_id}, then appends the fixed output-requirements
+    block when *resolution* is given (docs/11 §7.1). The user's 话术 box holds
+    only the creative part; structural requirements are appended by code.
+    """
+    rendered = str(template).replace("{title}", task.title).replace(
+        "{product_id}", task.product_id)
+    return rendered + build_output_requirements(resolution)
 
 
 def safe_product_filename(product_id):
@@ -88,7 +112,7 @@ def generate_outfit_image(
         raise TypeError("task must be OutfitTask")
 
     try:
-        prompt = render_prompt(prompt_template, task)
+        prompt = render_prompt(prompt_template, task, resolution=resolution)
         client = api_client or ImageApiClient(model_config)
         image_bytes = client.generate(prompt, task.garment_path, resolution=resolution)
         output_path = make_outfit_output_path(output_dir, task.product_id)