[core] Define Position, LiquidationOpportunity, FlashLoanSource, SwapRoute types

[obchain]

Context

Normalized data shapes used across every layer. Every lending protocol (Venus now, Aave / Compound / Morpho later) reduces to the same Position type after the adapter layer, so scanner and executor stay protocol-agnostic.

Scope

• Position — borrower, collateral/debt tokens and amounts, health factor, liquidation bonus
• LiquidationOpportunity — a profitable, ready-to-execute liquidation
• FlashLoanSource — enum: BalancerV2 (0%), AaveV3 (0.05%), UniswapV3 (pool fee)
• SwapRoute — planned collateral → debt DEX swap with slippage protection
• ProtocolId — enum naming the protocol (Venus for v1)
• LiquidationParams — protocol-specific call parameters (Venus variant for v1)
• All types derive Serialize / Deserialize for config + logging

Acceptance criteria

• All six types defined in charon-core/src/types.rs
• Address and U256 from alloy::primitives used correctly
• All types derive Debug, Clone, Serialize, Deserialize
• charon-core compiles with alloy + serde as dependencies

References

• Delivered in commit 2371853
• PRD section 3a (Core Types)

[obchain]

Superseded — core types shipped in feat/02-core-types.