fix: provide unique metric identity for workers

[ferhatelmas]

What kind of change does this PR introduce?

Bug fix

What is the current behavior?

Under Watt metrics can conflict with same hostname.

What is the new behavior?

Give unique writer identity:

• hostname:applicationId:worker:<workerId>
• hostname:pid:<process.pid>

Additional context

Also, add service.name into example collector config, was forgotten in #1112

[Copilot]

Pull request overview

This PR fixes OpenTelemetry metric writer collisions (notably under Watt when multiple workers share the same hostname) by adding a stable, unique service instance identity to the metric Resource and ensuring it is propagated into Prometheus/remote-write label sets via the example collector config.

Changes:

• Derive a unique service.instance.id based on hostname + Platformatic application/worker identity (or PID fallback) and attach it to the OTel Resource.
• Expose additional identity/resource attributes (service.instance.id, worker.id, platformatic.application.id) as constant labels for the Prometheus exporter.
• Update the example OTel Collector config (and add tests) to copy these Resource attributes into datapoint attributes/labels (including service.name).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/internal/monitoring/otel-metrics.ts	Adds unique metric identity (service instance id + worker/app ids) to the OTel Resource and Prometheus constant-label filtering.
src/internal/monitoring/otel-metrics.test.ts	Adds coverage for Watt worker identity mapping and verifies collector config contains the new promotion rules.
monitoring/otel/config/otel-collector-config.yml	Promotes Resource identity attributes (and service.name) into metric datapoint attributes for stable routing/unique writer labels.

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[coveralls]

Coverage Report for CI Build 26952733055

Coverage increased (+0.04%) to 76.346%

Details

• Coverage increased (+0.04%) from the base build.
• Patch coverage: 18 of 18 lines across 1 file are fully covered (100%).
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	11029
Covered Lines:	8854
Line Coverage:	80.28%
Relevant Branches:	6452
Covered Branches:	4492
Branch Coverage:	69.62%
Branches in Coverage %:	Yes
Coverage Strength:	364.9 hits per line

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💛 - Coveralls