feat(sdk): Add SDK metrics and telemetry with pluggable exporters

[Kevin737866]

Description

Performance metrics with Prometheus/Datadog/console exporters.

Acceptance Criteria

• MetricsCollector: recordCall(method, duration, success, errorCode)
• Exporters: Console, Prometheus, Noop (default)
• Configurable via SDK: telemetry.enabled, telemetry.exporter
• Metrics: call_count, error_count, latency_p50/p95/p99
• Tests: recording, exporter interface, prometheus format

Files to Modify

• sdk/src/index.ts
• sdk/src/telemetry.ts
• sdk/src/types.ts

[habnark]

@habnark has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello can I work on this issue

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