feat: calculator widget

[pwltr]

Description

• adds calculator widget
• build widget component structure for non-slashfeed widgets
• migrate all currently saved widgets to add url field
• adds new widgets.json language resource as slashtags.json will be deprecated in the future

Linked Issues/Tasks

Closes #2400

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring (improving code without creating new functionality)

Tests

• Detox test
• Unit test
• No test

Screenshot / Video

Simulator.Screen.Recording.-.iPhone.16.-.2025-01-16.at.15.28.37.mp4

QA Notes

I tested migration path and backup/restore