Spec v0.9.0 compliance

[toddbaert]

Tracks spec v0.9.0 compliance. Significantly behind; several items depend on adding provider lifecycle + events first.

• [FEATURE] Implement Tracking in PHP #133 Tracking (spec 6)

• Add evaluation details to finally hook stage #140 Evaluation details in finally hook (breaking)

• Add OpenTelemetry-Compatible Telemetry Utility Function #143 Telemetry utility (Appendix D)

• [FEATURE] Update flagd-testbed (test-harness) #134 Update test-harness to v0.9.0

• Logging hook

• Hook data

• Provider lifecycle + shutdown reset (+ transaction context)

• Domain in provider init

• Provider status + events subsystem

• Provider lifecycle event ownership (race-condition fix): add opt-in marker so providers emit their own PROVIDER_READY/PROVIDER_ERROR; SDK derives status from the provider event stream and keeps + deprecates the legacy synthetic path; update first-party providers (spec 5.3.5, provider status 2.8, Appendix E)