[Sig Events] Add Sig Events Agent tools and skill

[mykolaharmash]

This change adds an events client for managing Sig Events and builds Agent tools on top to find, create and demote sig events.

[infra-vault-gh-plugin-prod]

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[mykolaharmash]

On the otel_demo dataset, the onboarding task was consistently over 5 minutes. 15 seems to be enough.

[kibanamachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: e869bc5

Failed CI Steps

• affected Scout: [ platform / osquery ] plugin

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
datasetQuality	1076	1077	+1
streamsApp	1843	1844	+1
total			+2

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
@kbn/streams-schema	395	401	+6

Any counts in public APIs

Total count of every any typed public API. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats any for more detailed information.

id	before	after	diff
@kbn/streams-schema	14	15	+1

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
datasetQuality	524.5KB	526.5KB	+2.0KB
streamsApp	2.0MB	2.0MB	+2.0KB
total			+4.0KB

Unknown metric groups

API count

id	before	after	diff
@kbn/streams-schema	484	490	+6

References to deprecated APIs

id	before	after	diff
@kbn/streams-schema	3	4	+1

Unreferenced deprecated APIs

id	before	after	diff
@kbn/streams-schema	3	4	+1

[mykolaharmash]

Superseded by #271430