Feature/sc 005 verification aggregation engine

[Tobi-8]

Summary

• Added VerificationAggregator — a deterministic, integer-only weighted consensus engine (SC-005).
• Aggregates every claim verification into trueWeight/falseWeight/totalWeight via the IVerificationSource interface, with weight = frozen effectiveStake recorded by TruthBountyWeighted at vote time.
• Computes canonical ClaimOutcome (VERIFIED_TRUE / VERIFIED_FALSE / INCONCLUSIVE) and a 0–10 000 bps confidence score.
• Deterministic tie handling: equal weights, zero participation, and sub-threshold outcomes resolve to INCONCLUSIVE; no randomness.
• Configurable minimum-participation thresholds (count, total weight, confidence) enforced in aggregateClaim.
• Exposes aggregateClaim(), getAggregation(), calculateConfidence(), calculateWeights(); emits ClaimAggregated.
• Pure consensus calculator — never settles, slashes, or transfers funds; extensible to reputation/quadratic/committee weighting without storage changes.
• TruthBountyWeighted exposes minimal getClaimVoterCount/getClaimVoterAt/getVoteData view functions for the aggregator.
• Resolved pre-existing compile blockers on main (PAUSER_ROLE in BootstrapController/MigrationManager, GOVERNANCE_ROLE getter, RewardEngine stack-too-deep) so the suite compiles and CI can run.

Testing

• 36 tests in test/VerificationAggregator.test.ts: unanimous TRUE/FALSE, mixed, weighted majorities, ties → INCONCLUSIVE, threshold enforcement, idempotency, determinism (same vote multiset in different orders → identical results), 100-verifier stress (decisive + tie), and gas benchmarks.
• Full suite: 352 passing. 28 pre-existing failures remain on main in unrelated features (BootstrapController bootstrap flow, ExampleSettlement, StaleReputation, TieResolution, TruthBountyWeighted) — verified present independent of this change.
• Gas (hardhat, solc 0.8.28, runs 200): calculateWeights ≈122k (10 votes) / ≈961k (100 votes); aggregateClaim ≈225k / ≈1 063k; getAggregation ≈35k (constant); cost scales ~linearly (~9.3k gas/vote).

Closes #285