feat: real-time on-chain sale notifications for producers

[brightpixel-dev]

Difficulty: Hard · Priority: Critical

Overview

Producers currently have no way to learn a beat sold other than manually reopening Profile and comparing the earnings number to before. Add in-app notifications driven by on-chain sale events.

Acceptance Criteria

• Bell icon + dropdown in the navbar showing recent sale notifications
• New sale while connected surfaces a toast + adds to the list
• Read/unread state persisted per wallet address
• No-op gracefully when contract ID env var is unset

Technical Approach

Poll Soroban getEvents for purchase_license/withdraw_earnings topics with a persisted cursor, filter to events involving the connected address, resolve sample info via get_sample, store dismissed/read state client-side.

New event-driven state layer with no existing precedent in this codebase (cursor persistence, de-dup, pagination against RPC retention limits) — a new subsystem, not a component tweak.

[mxrtins04]

Hi maintainer, can i be assigned this issue pleasee?

[blurbeast]

hello my Chief, can i jump on this please ??