V2-SC-007: Enforce Claim Lifecycle and Deadline Transitions

[ugoocreates-pixel]

Closes #358

Implements the canonical claim state machine and reusable transition guards.

Technical Scope

• ClaimState Update: Modified IV2Types.ClaimState to support VerificationOpen, ChallengeWindow, AwaitingSettlement, Disputed, and Finalized transitions.
• State Machine Rules: Updated V2Lifecycle.sol logic to correctly enforce transitions between the canonical claim states.
• Event Signature: Replaced the legacy ClaimStatusChanged with ClaimStateChanged mapping (uint256 indexed claimId, IV2Types.ClaimState previousState, IV2Types.ClaimState newState, address indexed actor, uint64 timestamp, bytes32 reasonCode) in IClaims.sol.
• Query Utilities: Re-mapped isClaimOpen, isClaimVerified, and isClaimDisputed inside V2Lifecycle to reflect the respective groupings under the new enumeration.

Security and Integrity Requirements Maintained

• Immutability of Finalized States: A finalized claim can never return to an earlier state; Finalized is strictly validated as a terminal state.
• Invariant Guarantee: Reused strict V2Errors.InvalidClaimStateTransition boundaries.