Emit config-change events and add settlementPaused ops guidance

[MontrealAI]

Motivation

• Improve operational observability by emitting explicit old→new events for remaining high-impact setter functions so operator actions are auditable without changing behavior.
• Make the pause/runbook guidance explicit about the separate settlementPaused control (emergency settlement freeze) and the correct incident sequencing to avoid accidental fund-out during incidents.

Description

• In contracts/AGIJobManager.sol capture prior values, perform the assignment, and emit old/new events for the following setters: updateAGITokenAddress, setEnsJobPages, setUseEnsJobTokenURI, setVoteQuorum, setRequiredValidatorApprovals, setRequiredValidatorDisapprovals, setValidationRewardPercentage, setAgentBondParams (emits on both zeroing and non-zeroing branches), setAgentBond, and setValidatorSlashBps.
• Preserved existing validation, access control, and function signatures; emits are additive and placed after state updates to reflect final state.
• ENS hook visibility requirement was already satisfied: EnsHookAttempted event and _callEnsJobPagesHook emission remain in place and unchanged functionally (still gas-capped and non-blocking).
• Doc updates: docs/operator-runbook.md and docs/ops/parameter-safety.md were minimally edited to explicitly document settlementPaused, list the settlement-gated functions, and recommend calling setSettlementPaused(true) first (then pause()) during incidents; recovery sequencing guidance was also adjusted.
• No changes to truffle-config.js or compiler settings and no refactors of unrelated code were made.

Testing

• Performed static repo inspection (searches and file diffs) to confirm the new emits and that the ENS hook event is present; no runtime or CI tests were executed.
• No automated unit or integration tests were added or run as part of this change.

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Codex Task