[GF-FE-07] Build admin hub settings page /admin/settings

[yusuftomilola]

Problem

There is no settings page for admins to configure hub-wide settings (name, hours, timezone, tax rate). Without this UI, hub operators must hard-code configuration or contact developers to make basic customisations.

Proposed Solution

Create frontend/app/admin/settings/page.tsx as a settings form that reads from and writes to the GET/PATCH /hub-settings endpoints (implemented in GF-BE-03).

Page sections:

1. Basic Info — Hub Name, Description, Contact Email, Contact Phone, Logo (image upload via existing Cloudinary integration)
2. Business Hours — A per-day grid (Monday–Sunday) with a toggle (open/closed) and time inputs (open time, close time) for each day
3. Address — Full address text field
4. Tax & Currency — Tax Rate (percentage input), Currency (read-only display showing "NGN")
5. Timezone — Dropdown of common African/global timezones

Each section has its own Save button (or one global Save at the bottom). Show a success toast on save and display validation errors inline.

Acceptance Criteria

• frontend/app/admin/settings/page.tsx created and accessible via /admin/settings
• Page is protected (admin/super_admin only)
• Page fetches current settings from GET /hub-settings on load and pre-populates the form
• Save calls PATCH /hub-settings and shows a success or error toast
• Business hours grid correctly renders toggles and time inputs for all 7 days
• Logo upload uses the existing Cloudinary image upload component
• Page is linked from the admin sidebar navigation

Depends on: [GF-BE-03] Build hub settings backend module (name, hours, timezone, tax rate)

[YaronZaki]

@YaronZaki has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Kindly assign, I am an experienced developer.

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[grantfox-oss]

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Next steps:

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Congratulations, @YaronZaki! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign campaign!

@YaronZaki's PR #1318 was approved and merged by @yusuftomilola.

🏆 @YaronZaki: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (261 total points). Track your full progress on GrantFox.

👏 Great work, @YaronZaki! Keep contributing to DistinctCodes.

[drips-wave]

This issue has been completed by @YaronZaki as part of the Stellar Wave Program's 6th Wave 🥳

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