feat: add subscription management panel (#163)

[gTanusri]

Summary

• Adds a SuperAdmin-only subscription management panel.
• Supports creating, editing, deleting, and searching subscription plans.
• Supports creating, editing, deleting, and searching subscription features.
• Supports assigning features to plans and assigning plans to restaurants.
• Adds current restaurant subscription lookup.
• Adds SuperAdmin-only sidebar visibility for subscription management.

Issue

Closes #163

Verification

• npm run build
• npm run lint

[rdodiya]

Hi @gTanusri,

I noticed a couple of UI issues while testing:

• The values entered in the input fields are not visible, as shown in the attached video. It appears the input text color is white, making it unreadable in the current theme.
• Please ensure all forms are theme-friendly. Form backgrounds, input fields, labels, and text colors should adapt correctly for both Dark and Light modes, as shown in the screenshot.

Kindly update the styling so that:

• Input values are always clearly visible.
• Forms follow the selected theme consistently across the application.
• Text, placeholders, borders, and backgrounds have sufficient contrast in both themes.

Please test the forms in both Dark and Light modes before updating the PR.

PR-254-1.mp4

[gTanusri]

Hi @rdodiya,

I’ve updated the admin form styling so input values, placeholders, textareas, selects, and select options remain readable in both light and dark modes. This should fix the invisible input text issue and make the subscription forms theme-friendly.