feat(contract): implement an explicit pause policy for every value-moving operation

[arisu6804]

Problem

Emergency controls are ambiguous when some value-moving paths remain callable during an incident.

Objective

Deliver a production-quality improvement to pause controls and value-moving entrypoints that creates measurable value for correctness, security, reliability, performance, or maintainability.

Implementation scope

• Enumerate deposits, withdrawals, transfers, claims, and administrative recovery paths.
• Apply a governed pause check consistently and keep only explicitly documented read-only paths available.
• Emit pause and unpause events with caller and reason metadata where supported.

Acceptance criteria

• Every value-moving operation has a tested paused behavior.
• Read-only inspection remains available and does not mutate state.
• Pause authority and recovery behavior are explicit and auditable.

Required validation

• Entrypoint matrix tests, authorization tests, paused-state rollback tests, and event assertions.
• Existing tests and CI remain passing.
• Add regression coverage for the original failure mode.
• Do not weaken, delete, or skip unrelated tests to obtain a green build.

PR quality bar

• Keep the PR focused on this issue and explain design tradeoffs.
• Include test evidence, compatibility impact, and migration or rollout notes where relevant.
• Avoid typo-only, documentation-only, cosmetic-only, or unrelated refactor submissions.

Out of scope

• Broad rewrites not required by the acceptance criteria.
• Changes to unrelated services, contracts, or user flows.