feat: implement F8B O2 exact-output execution and evidence

[garykocsis]

Summary

Implements F8B — O2 Exact-Output Execution / Execution Evidence.

This slice binds an authorized Standby exercise to exactly one qualifying protected PoolManager swap and records authoritative execution evidence only after the matching swap produces exactly the authorized protected output.

What changed

• added the AUTHORIZED → EXECUTING → EXECUTED protected-execution lifecycle
• classified only the exact authorized protected swap as O2
• rejected mismatched, nested, repeated, or unrelated swaps while an O2 causal context is active
• used authoritative PoolManager afterSwap evidence to prove exact protected output
• added ExerciseRouter coordination for the single protected exact-output execution
• reused the canonical protected-execution reconstruction across authorization and execution
• added test-only mechanical delta closure for real-PoolManager F8B verification without introducing F8C settlement semantics
• added integration, unit, fuzz, perimeter, adversarial, direction-generality, and prediction-vs-actual execution evidence
• adapted F8A tests to the now-executing O2 path
• corrected stale F8A-era documentation following independent review
• updated project status after independent G8B closure

Responsibility boundary

F8B establishes authoritative AMM execution evidence only.

It does not implement input settlement, maxInput enforcement, direct Beneficiary delivery, Remaining Entitlement reduction, obligation reduction, fulfillment, or finalization. Those responsibilities remain downstream.

Verification

• forge fmt --check
• forge lint
• forge build
• forge test
• FOUNDRY_PROFILE=ci forge test

Full test suite: 466 passed, 0 failed, 0 skipped.

Gate

G8B: PASS

F8B was independently reviewed against its pre-derived responsibility and verification gate.

Next implementation slice: F8C — Authoritative Settlement / Direct Beneficiary Delivery.