feat: 模板与剪辑计划后端能力补齐

- 模板复制接口（含所有片段配置）
- 模板列表多维度筛选（分类/标签/关键词/模式）
- 模板标签聚合接口（去重排序）
- 模板使用次数统计
- TemplateResponse 新增 usage_count 字段
- 新增 CountTemplatesUseCase / CopyTemplateUseCase / ListTagsUseCase / GetTemplateUsageUseCase
- 35个模板相关单元测试全部通过

packages/adapters/sqlalchemy_impl/template_repository.py

@@ -2,11 +2,14 @@
 
 from __future__ import annotations
 
+import uuid
 from typing import List, Optional
 
+from sqlalchemy import func
 from sqlalchemy.orm import Session
 
 from packages.adapters.sqlalchemy_impl.models import (
+    EditPlanModel,
     TemplateCategoryModel,
     TemplateModel,
     TemplateSegmentModel,
@@ -28,13 +31,27 @@ class SQLAlchemyTemplateRepository:
         *,
         skip: int = 0,
         limit: int = 50,
+        category: Optional[str] = None,
+        tag: Optional[str] = None,
+        keyword: Optional[str] = None,
+        mode: Optional[str] = None,
     ) -> List[Template]:
+        query = self.session.query(TemplateModel).filter(
+            TemplateModel.user_id == user_id,
+            TemplateModel.is_active.is_(True),
+        )
+        if category:
+            query = query.filter(TemplateModel.category == category)
+        if mode:
+            query = query.filter(TemplateModel.mode == mode)
+        if keyword:
+            like_pattern = f"%{keyword}%"
+            query = query.filter(TemplateModel.name.like(like_pattern))
+        if tag:
+            # JSON 数组包含指定标签（MySQL JSON_CONTAINS / SQLite json_each 兼容写法用 LIKE）
+            query = query.filter(TemplateModel.tags.like(f'%"{tag}"%'))
         models = (
-            self.session.query(TemplateModel)
-            .filter(
-                TemplateModel.user_id == user_id,
-                TemplateModel.is_active.is_(True),
-            )
+            query
             .order_by(TemplateModel.created_at.desc())
             .offset(skip)
             .limit(limit)
@@ -142,15 +159,77 @@ class SQLAlchemyTemplateRepository:
         self.session.commit()
         return True
 
-    def count_by_user(self, user_id: str) -> int:
-        return (
-            self.session.query(TemplateModel)
-            .filter(
-                TemplateModel.user_id == user_id,
-                TemplateModel.is_active.is_(True),
-            )
-            .count()
+    def count_by_user(
+        self,
+        user_id: str,
+        *,
+        category: Optional[str] = None,
+        tag: Optional[str] = None,
+        keyword: Optional[str] = None,
+        mode: Optional[str] = None,
+    ) -> int:
+        query = self.session.query(TemplateModel).filter(
+            TemplateModel.user_id == user_id,
+            TemplateModel.is_active.is_(True),
         )
+        if category:
+            query = query.filter(TemplateModel.category == category)
+        if mode:
+            query = query.filter(TemplateModel.mode == mode)
+        if keyword:
+            query = query.filter(TemplateModel.name.like(f"%{keyword}%"))
+        if tag:
+            query = query.filter(TemplateModel.tags.like(f'%"{tag}"%'))
+        return query.count()
+
+    def copy_template(self, template_id: str, user_id: str, new_name: str) -> Template:
+        """复制模板（含所有 segments）。"""
+        source = self.get(template_id, user_id)
+        if source is None:
+            raise ValueError(f"Template {template_id} not found")
+
+        new_id = str(uuid.uuid4())
+        new_template = Template(
+            id=new_id,
+            user_id=user_id,
+            name=new_name,
+            mode=source.mode,
+            category=source.category,
+            tags=list(source.tags),
+            title_config=dict(source.title_config),
+            subtitle_config=dict(source.subtitle_config),
+            bgm_config=dict(source.bgm_config),
+            estimated_duration=source.estimated_duration,
+            is_active=True,
+        )
+        created = self.create(new_template)
+
+        # 复制 segments
+        new_segments: List[TemplateSegment] = []
+        for seg in source.segments:
+            new_seg = TemplateSegment(
+                id=str(uuid.uuid4()),
+                template_id=new_id,
+                segment_order=seg.segment_order,
+                duration_min=seg.duration_min,
+                duration_max=seg.duration_max,
+                material_type=seg.material_type,
+            )
+            new_segments.append(new_seg)
+            model = TemplateSegmentModel(
+                id=new_seg.id,
+                template_id=new_seg.template_id,
+                segment_order=new_seg.segment_order,
+                duration_min=new_seg.duration_min,
+                duration_max=new_seg.duration_max,
+                material_type=new_seg.material_type,
+            )
+            self.session.add(model)
+        if new_segments:
+            self.session.commit()
+
+        created.segments = new_segments
+        return created
 
     # ── Segments ──
 
@@ -234,6 +313,37 @@ class SQLAlchemyTemplateRepository:
         self.session.commit()
         return True
 
+    # ── Tags ──
+
+    def list_tags(self, user_id: str) -> List[str]:
+        """获取用户所有模板的标签（去重）。"""
+        models = (
+            self.session.query(TemplateModel)
+            .filter(
+                TemplateModel.user_id == user_id,
+                TemplateModel.is_active.is_(True),
+                TemplateModel.tags.isnot(None),
+            )
+            .all()
+        )
+        tags_set: set[str] = set()
+        for m in models:
+            if m.tags:
+                for t in m.tags:
+                    if t:
+                        tags_set.add(t)
+        return sorted(tags_set)
+
+    # ── Usage Stats ──
+
+    def get_usage_count(self, template_id: str) -> int:
+        """获取模板被使用的次数（关联的剪辑计划数量）。"""
+        return (
+            self.session.query(EditPlanModel)
+            .filter(EditPlanModel.template_id == template_id)
+            .count()
+        )
+
     # ── Mapping helpers ──
 
     @staticmethod