Optimize shot table loading performance

- Pass episode_id filter to backend API instead of client-side filtering,
  reducing payload size when an episode is selected
- Skip getShot refetch in ShotDetailPanel when initialShot prop is provided
- Fix redundant DB query in list_shots: read project.custom_task_statuses
  directly from the already-fetched project object
- Add missing indexes on Task.shot_id, Task.assigned_user_id,
  Task.deleted_at and Episode.project_id; add add_perf_indexes.py
  migration script to apply them to existing databases
- Center login page layout
- Update CLAUDE.md and AGENTS.md with correct venv path

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/schemas/shot.py

@@ -28,6 +28,14 @@ class ShotUpdate(BaseModel):
     project_id: Optional[int] = Field(None, description="Project ID - must match episode's project")
 
 
+class TaskStatusInfo(BaseModel):
+    """Task status information for table display"""
+    task_type: str  # String to support custom task types
+    status: str  # Changed from TaskStatus enum to str to support custom statuses
+    task_id: Optional[int] = None
+    assigned_user_id: Optional[int] = None
+
+
 class ShotResponse(ShotBase):
     id: int
     project_id: int  # Make required in response
@@ -40,19 +48,16 @@ class ShotResponse(ShotBase):
     
     # Optional computed field for display
     project_name: Optional[str] = Field(None, description="Project name for display purposes")
+    
+    # Task status information for detail display
+    task_status: Dict[str, Optional[str]] = Field(default_factory=dict, description="Task status by task type")
+    task_ids: Dict[str, int] = Field(default_factory=dict, description="Task IDs by task type")
+    task_details: List[TaskStatusInfo] = Field(default_factory=list, description="Detailed task information")
 
     class Config:
         from_attributes = True
 
 
-class TaskStatusInfo(BaseModel):
-    """Task status information for table display"""
-    task_type: str  # String to support custom task types
-    status: str  # Changed from TaskStatus enum to str to support custom statuses
-    task_id: Optional[int] = None
-    assigned_user_id: Optional[int] = None
-
-
 class ShotListResponse(BaseModel):
     id: int
     name: str