Add invoice creator verification request flow

[Kingsman-99]

Description

VerifiedCreatorBadge.tsx displays a verified badge but there's no in-app flow for a creator to actually request verification — it must currently be granted out-of-band. This issue adds a request flow.

Technical Context

New src/app/settings/verify/page.tsx extension (the route already exists per src/app/settings/verify) and src/lib/verificationRequests.ts. Creator submits a verification request (display name, optional links) which is stored locally as pending status; admin approval mechanism is out of scope here (separate backend concern) — this issue covers the request submission and status display only.

Acceptance Criteria

• Request form collects display name and optional social/website links, with basic URL validation
• Submitted request shows a "Pending review" status badge on the settings page
• Duplicate submission while already pending is blocked with an explanatory message
• Request data structure is documented for whatever manual/admin process consumes it later
• Unit tests: URL validation, duplicate-submission blocking

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[1sraeliteX]

Hello, I would like to work on this issue