feat: 高级编辑共享跳过审核 + 去重 + 通知 + 已分享状态

共享流程:
- 高级编辑/管理员共享直接进公共库（跳过审核）
- 普通用户共享仍需管理员审核
- 高级编辑共享后通知管理员"已添加"（非待审核）

去重检测:
- 同名同内容：提示"已有一模一样的"
- 同名不同内容：提示改名后共享

状态显示:
- 共享后对比公共库内容，相同则显示"已共享"
- 修改内容后"已共享"消失，可重新共享

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/main.py

@@ -799,9 +799,16 @@ def create_recipe(recipe: RecipeIn, user=Depends(get_current_user)):
         c.execute("INSERT OR IGNORE INTO tags (name) VALUES (?)", (tag,))
         c.execute("INSERT OR IGNORE INTO recipe_tags (recipe_id, tag_name) VALUES (?, ?)", (rid, tag))
     log_audit(conn, user["id"], "create_recipe", "recipe", rid, recipe.name)
-    # Notify admin when non-admin/non-senior_editor creates a recipe (needs review)
-    if user["role"] not in ("admin", "senior_editor"):
-        who = user.get("display_name") or user["username"]
+    who = user.get("display_name") or user["username"]
+    if user["role"] == "senior_editor":
+        # Senior editor adds directly — just inform admin
+        conn.execute(
+            "INSERT INTO notifications (target_role, title, body) VALUES (?, ?, ?)",
+            ("admin", "📋 新配方已添加",
+             f"{who} 将配方「{recipe.name}」添加到了公共配方库。\n[recipe_id:{rid}]")
+        )
+    elif user["role"] not in ("admin",):
+        # Other users need review
         conn.execute(
             "INSERT INTO notifications (target_role, title, body) VALUES (?, ?, ?)",
             ("admin", "📝 新配方待审核",