feat: subgraph implementation for sentrix-dex (UniV2 fork)

[satyakwok]

Implement a Graph-protocol-style subgraph for sentrix-dex indexing. Pairs, swaps, mints, burns, syncs.

Why

Every UniV2-style DEX UI relies on a subgraph for historical data (charts, volume, top pairs). Sentrix-dex frontend currently reads on-chain directly + indexer endpoints — adequate but slow vs proper subgraph indexing for analytics.

Status

Manifest sketch exists at sentrix-labs/sentrix-bridge repo under subgraph/ (Phase 1 scope: PairCreated + Swap + Mint + Burn + Sync). Schema + AssemblyScript handlers drafted. Needs deployment target.

Hard prerequisite

• Graph hosted service does not yet support Sentrix (chainId 7119). Either:
  • Apply to The Graph for chain integration (1-3 months calendar)
  • Self-host graph-node Rust binary on operator infrastructure

Acceptance

• Subgraph deployable + indexes from genesis (or from sentrix-dex Factory deploy block)
• Public GraphQL endpoint
• Frontend integration verified