Add config-change events to ENSJobPages

[MontrealAI]

Motivation

• Improve ops telemetry so owner-controlled configuration changes in ENSJobPages are auditable with explicit old→new event pairs.
• Capture high-impact updates (ENS registry, name wrapper, resolver, jobs root, job manager, and token-URI flag) for postmortems and monitoring without changing runtime behavior.
• Keep changes minimal and localized to contracts/ens/ENSJobPages.sol and preserve existing access control and validation.

Description

• Added event declarations: ENSRegistryUpdated, NameWrapperUpdated, PublicResolverUpdated, JobsRootUpdated, JobManagerUpdated, and UseEnsJobTokenURIUpdated adjacent to existing events.
• Updated setters setENSRegistry, setNameWrapper, setPublicResolver, setJobsRoot, setJobManager, and setUseEnsJobTokenURI to read the old value into a local, perform the existing checks and assignment unchanged, then emit the corresponding old/new event.
• Kept all public/external signatures, validations, and internal logic unchanged, and limited edits to a single file contracts/ens/ENSJobPages.sol.

Testing

• No automated tests were executed for this change.

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Codex Task