update: 重构后台任务展示，采用悬浮窗样式

backend/alembic/postgres/env.py

@@ -25,7 +25,8 @@ from app.models import (
     Settings, WritingStyle, ProjectDefaultStyle,
     RelationshipType, CharacterRelationship, Organization, OrganizationMember,
     StoryMemory, PlotAnalysis, AnalysisTask, BatchGenerationTask,
-    RegenerationTask, Career, CharacterCareer, User, MCPPlugin, PromptTemplate
+    RegenerationTask, Career, CharacterCareer, User, MCPPlugin, PromptTemplate,
+    BackgroundTask
 )
 
 # Alembic Config 对象

backend/alembic/sqlite/env.py

@@ -25,7 +25,8 @@ from app.models import (
     Settings, WritingStyle, ProjectDefaultStyle,
     RelationshipType, CharacterRelationship, Organization, OrganizationMember,
     StoryMemory, PlotAnalysis, AnalysisTask, BatchGenerationTask,
-    RegenerationTask, Career, CharacterCareer, User, MCPPlugin, PromptTemplate
+    RegenerationTask, Career, CharacterCareer, User, MCPPlugin, PromptTemplate,
+    BackgroundTask
 )
 
 # Alembic Config 对象

backend/alembic/sqlite/versions/20260427_1200_def45678ghi9_添加后台任务表.py

@@ -28,7 +28,7 @@ def upgrade() -> None:
         sa.Column('status_message', sa.String(), nullable=True),
         sa.Column('progress_details', sa.Text(), nullable=True),
         sa.Column('error_message', sa.Text(), nullable=True),
-        sa.Column('task_params', sa.Text(), nullable=True),
+        sa.Column('task_input', sa.Text(), nullable=True),
         sa.Column('task_result', sa.Text(), nullable=True),
         sa.Column('cancel_requested', sa.Boolean(), default=False),
         sa.Column('retry_count', sa.Integer(), default=0),