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>

client/public/locales/en/common.json

@@ -37,6 +37,19 @@
         "viewAll": "View All"
     },
     "warnWhenUnsavedChanges": "Are you sure you want to leave? You have unsaved changes.",
+    "batch": {
+        "selected": "{{count}} selected",
+        "clear_selection": "Clear",
+        "archive_confirm": "Archive Spools",
+        "archive_confirm_content": "Are you sure you want to archive {{count}} spools?",
+        "unarchive_confirm": "Unarchive Spools",
+        "unarchive_confirm_content": "Are you sure you want to unarchive {{count}} spools?",
+        "delete_confirm": "Delete Spools",
+        "delete_confirm_content": "Are you sure you want to delete {{count}} spools? This action cannot be undone.",
+        "move": "Move",
+        "move_title": "Move Spools to Location",
+        "move_description": "Select a location for the {{count}} selected spools."
+    },
     "notifications": {
         "success": "Successful",
         "error": "Error (status code: {{statusCode}})",
@@ -239,6 +252,40 @@
             "last_used": "Last used {{date}}"
         }
     },
+    "location": {
+        "location": "Location",
+        "locations": "Locations",
+        "create": "Create Location",
+        "titles": {
+            "create": "Create Location",
+            "edit": "Edit Location",
+            "list": "Locations"
+        },
+        "fields": {
+            "name": "Name",
+            "name_required": "Location name is required",
+            "name_placeholder": "e.g., Shelf A",
+            "parent": "Parent Location",
+            "parent_placeholder": "Select parent (optional)",
+            "location_type": "Type",
+            "location_type_placeholder": "Select type (optional)",
+            "description": "Description",
+            "spool_count": "Spools",
+            "full_path": "Full Path"
+        },
+        "types": {
+            "room": "Room",
+            "shelf": "Shelf",
+            "bin": "Bin",
+            "drawer": "Drawer",
+            "box": "Box",
+            "other": "Other"
+        },
+        "messages": {
+            "delete_confirm": "Are you sure you want to delete this location?",
+            "has_children": "This location has child locations"
+        }
+    },
     "filament": {
         "filament": "Filaments",
         "fields": {
@@ -336,7 +383,21 @@
         "description": "It looks like you haven't added any spools yet. See the <helpPageLink>Help page</helpPageLink> for help getting started.",
         "all_spools": "All Spools",
         "low_stock_alert": "{{count}} spools below {{threshold}}g",
-        "low_stock_warning": "Low stock"
+        "low_stock_warning": "Low stock",
+        "alerts": {
+            "low_stock": "Low Stock",
+            "pending_jobs": "Pending Jobs",
+            "needs_weighing": "Needs Weighing"
+        },
+        "charts": {
+            "material_distribution": "Material Distribution"
+        },
+        "quick_stats": {
+            "total_spools": "Total Spools",
+            "total_filaments": "Filament Types",
+            "total_vendors": "Vendors",
+            "total_weight": "Total Remaining"
+        }
     },
     "help": {
         "help": "Help",