ArbSphere MVP Contracts: Toy DSL Seeds and Canonical IR

This document provides small, self-contained seeds for ArbSphere primitives that can be used by adapters to bootstrap interoperability in a two-venue MVP. The seeds follow the CatOpt-inspired canonical IR mapping used by EnergiBridge-like bridges.

Primitives (DSL seeds)
- LocalArbProblemSeed
  - id: string
  - venue: string
  - asset_pair: string (e.g. "AAPL/MSFT")
  - target_misprice: float
  - max_exposure: float
  - latency_budget_ms: int

- SharedSignalsSeed
  - version: int
  - price_delta: float
  - cross_venue_corr: float
  - liquidity: float

- PlanDeltaSeed
  - actions: list of dicts with keys {venue_from, venue_to, instrument, size, time}
  - timestamp: ISO8601 string
  - delta_id: string
  - signer: string (optional)
  - signature: string (optional)

- DualVariablesSeed
  - multipliers: dict
  - version: int

- PrivacyBudgetSeed
  - limit: float
  - remaining: float
  - expiration: ISO8601 string

- AuditLogSeed
  - entries: list of AuditLogEntrySeed

- AuditLogEntrySeed
  - ts: ISO8601 string or numeric
  - event: string
  - details: dict
  - signature: string

Example: two-venue MVP seed composition
```
LocalArbProblemSeed: {
  id: "seed-venue-A-1",
  venue: "venue-A",
  asset_pair: "AAPL/MSFT",
  target_misprice: 0.5,
  max_exposure: 10000.0,
  latency_budget_ms: 50
}
SharedSignalsSeed: {
  version: 1,
  price_delta: 0.12,
  cross_venue_corr: 0.75,
  liquidity: 20000.0
}
PlanDeltaSeed: {
  actions: [ {venue_from: "venue-A", venue_to: "CROSS-VENUE", instrument: "AAPL/MSFT", size: 100, time: "2026-01-01T00:00:00Z"} ],
  timestamp: "2026-01-01T00:00:00Z",
  delta_id: "delta-001",
  signer: "arb-issuer",
  signature: "sig"
}
```

Usage guidance
- Adapters should map their vendor-specific data to these seeds before translation into the canonical IR.
- The seeds are intended to be minimal, deterministic, and extensible as more primitives are added.

Sanity checks
- Validate that LocalArbProblemSeed.asset_pair is two-tuple string when exported to IR.
- Ensure that PlanDeltaSeed.actions are deduplicated in downstream merges to support deterministic replay.