feat(sdk): Add telemetry package to support sinks

[namrataghadi-galileo]

Summary

Added a new shared top-level telemetry/ package to hold common telemetry contracts and trace-context primitives used across AgentControl.

Refactored the SDK observability write path to use the shared ControlEventSink contract internally while preserving the existing default OSS behavior: queue-backed batching and delivery to /api/v1/observability/events.

Aligned telemetry packaging with the existing models/engine bundling pattern so telemetry is vendored into SDK and server builds rather than treated as a separate runtime-only dependency.

Scope

User-facing / API changes

• No intended user-facing behavior changes.
• No change to default OSS event delivery behavior.
• No new public sink-selection API in this story.

Internal changes

• Introduced shared telemetry types: ControlEventSink, SinkResult, BaseControlEventSink, and shared trace-context helpers.
• Removed SDK-local ownership of trace-context internals and pointed SDK code/tests to the shared telemetry package.
• Updated SDK observability internals so event writes flow through the shared sink contract.
• Updated build/package wiring so telemetry is bundled like models and engine.

Out of scope

• Server write-path refactor to the shared sink contract.
• Config-driven sink selection.
• OTEL sink implementation and OTEL settings.
• Any changes to /observability/events server ingestion behavior.

Risk and Rollout

Risk level: Medium

Rollback plan:

1. Revert the telemetry package introduction and SDK observability refactor.
2. Restore the previous SDK-local telemetry module and direct batcher-based event writes.
3. Remove telemetry vendoring from SDK/server build configuration.

Testing

• Added or updated automated tests
• Ran make check (or explained why not)

Focused validation is still pending locally; mypy surfaced follow-up packaging/type issues during development and we have been resolving those incrementally.

• Manually verified behavior

Checklist

• Linked issue/spec (if applicable)
• Updated docs/examples for user-facing changes

No docs/example updates were needed because this story is internal-only and no repo examples referenced the old telemetry module path.

• Included any required follow-up tasks

[codecov]

Codecov Report

❌ Patch coverage is 98.55072% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
sdks/python/src/agent_control/observability.py	96.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[lan17]

telemetry/ is now a standalone workspace package, but it is not wired into the repo's standard validation path. Please add it to the normal make lint, make typecheck, and make test/CI coverage so it can't drift outside the usual gates.

I also think it should have its own direct tests, even if they stay lightweight. Right now the package only gets incidental coverage through SDK/server tests, but the package itself owns behavior like trace-context validation and the sync/async sink contract. Those are simple enough to unit test directly in telemetry/, and package-local tests will make refactors safer than relying only on downstream coverage.

[namrataghadi-galileo]

Build & CI Integration

Root validation now includes telemetry in make test, make lint, and make typecheck.
Added a package-local Makefile so those forwarded targets behave like the other workspace packages.

CI/code coverage now picks up telemetry coverage output, with Codecov path-fixing added for the new package.

• ci.yml
• codecov.yml

Tests & Validation

• Added direct telemetry tests for trace-context validation and sink contracts.
• Tightened provider validation so blank/whitespace IDs are rejected consistently.
• Added async sink contracts plus tests so the package owns both sync and async behavior explicitly.

[lan17]

The telemetry coverage gap is addressed. telemetry/ now has direct tests plus Makefile and CI wiring for test/lint/typecheck, which was the missing piece I called out earlier.