feat: Add batch operations, dashboard redesign, hierarchical locations

## Batch Operations (#13)
- Add POST /spool/bulk/archive, /bulk/delete, /bulk/update endpoints
- Add row selection with checkboxes to spool list
- Add floating BatchActionBar with archive/unarchive/delete/move actions
- Add confirmation modals for all batch operations

## Dashboard Redesign (#12)
- Install recharts for pie charts
- Add AlertCards (low stock, pending jobs, needs weighing)
- Add MaterialDistributionChart (pie chart by material)
- Add QuickStats row (total spools, filaments, vendors, weight)
- Refactor home page layout with new components

## Hierarchical Locations (#9)
- Add Location model with self-referential parent relationship
- Add migration for location table and spool.location_id FK
- Add location database operations (CRUD, tree, full path)
- Add location API endpoints (list, tree, CRUD)
- Add LocationTreeSelect component with nested tree display
- Add LocationCreateModal for inline location creation
- Keep legacy location string field for backward compatibility

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

spoolman/api/v1/router.py

@@ -15,7 +15,7 @@ from spoolman.database.database import backup_global_db
 from spoolman.exceptions import ItemNotFoundError
 from spoolman.ws import websocket_manager
 
-from . import auth, backup as backup_module, export, externaldb, field, filament, models, other, print_job, setting, spool, vendor
+from . import auth, backup as backup_module, export, externaldb, field, filament, location as location_module, models, other, print_job, setting, spool, vendor
 
 logger = logging.getLogger(__name__)
 
@@ -116,3 +116,4 @@ app.include_router(export.router)
 app.include_router(backup_module.router)
 app.include_router(print_job.router)
 app.include_router(auth.router)
+app.include_router(location_module.router)