Latest raindex should support Flare end-to-end

[thedavidmeister]

The latest raindex should fully support the Flare network. Audit and wire Flare through the current version across every layer, filling any gaps:

• Contracts/deploy: current RaindexV6 (+ arb takers, flash borrower, subparser, route processor) deployed on Flare with pinned _0_1_x deploy constants matching the latest bytecode.
• Subgraph: Flare entry in subgraph/networks.json + a correct start block; subgraph deployable/indexable on Flare.
• Webapp: Flare selectable as a network (chain config, RPCs, token lists, explorer links).
• SDK / dotrain registry: Flare chain id supported in the client/registry so orders can be built, deployed, quoted, and managed on Flare.

Goal: a user can deploy and manage orders on Flare with the latest raindex with no missing-network gaps. Scope to be refined against the actual current state of each layer.

Co-Authored-By: Claude noreply@anthropic.com

[linear]

RAI-1021