Add Offerbook Sync

[offerbook]

Adds Offerbook Sync, a read-only Grand Exchange journal sync for offerbook.gg.

What it does

• Subscribes to GrandExchangeOfferChanged only and batches the user's own offer lifecycle events (placed / partial fill / cancelled / completed) to their offerbook.gg account, which builds an automatic flip journal there.
• No overlays, no menu entries, no input, nothing sent to the game server, no automation of any kind. It does not suggest or place offers.

Network / data (opt-in)

• Nothing is sent until the user pastes a token from offerbook.gg -> Account -> Connect RuneLite. Tokens are write-only and revocable.
• Fields sent: item id, GE slot, buy/sell, offer state, price, total quantity, filled quantity, gp spent, client timestamp, a random per-offer id generated locally (dedupes relog replays), and Client#getAccountHash() as hex (separates multiple accounts). No display names, chat, location, or credentials.
• Single fixed endpoint: https://offerbook.gg/api/ingest/trades (HTTPS, POST, batched every 10s, max 100 events per batch).
• Third-party warning included in the manifest.

No third-party dependencies. BSD-2-Clause.

[runelite-github-app]

New plugin offerbook-sync: https://github.com/offerbook/offerbook-sync/tree/aeda635aaa1ea8f5b0858f4f0666df7e97c36534