chore(server): improve the code related to otel

[soneda-yuya]

Overview

• change export from Google exporter to OTLP exporter
• add env values to set params in details.
• fix internal api errors which happens on visualizer internal api
  • if otel enable is false, application don't send request for otel
  • I will change internal api infrastructure after merging this PR to be enable otel on it.

What I've done

What I haven't done

How I tested

Which point I want you to review particularly

Memo

Checklist

• Verified backward compatibility related to feature modifications (if not compatible, reported deployment notes to the next release owner).
• Confirmed backward compatibility for migrations.
• Verified that no personally identifiable information (PII) is included in any values that may be displayed.

[Copilot]

Pull request overview

This PR refactors the OpenTelemetry tracing implementation by replacing the Google Cloud Platform-specific trace exporter with a more flexible OTLP (OpenTelemetry Protocol) exporter. The changes introduce support for multiple exporter types (GCP, Jaeger, and OTLP) configurable via environment variables, providing better flexibility for different deployment environments.

Key changes:

• Replaced GCP-specific trace exporter with OTLP exporter that supports multiple backends
• Added comprehensive environment variable configuration for OpenTelemetry settings
• Restructured tracing code into a dedicated otel package with improved separation of concerns

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
server/internal/app/otel/otel.go	New package implementing OTLP-based tracer initialization with support for GCP, Jaeger, and generic OTLP exporters
server/internal/app/otel/middleware.go	New middleware wrapper for Echo framework with path-based trace skipping
server/internal/app/config/config.go	Added OpenTelemetry configuration fields for endpoint, exporter type, batching, and sampling
server/internal/app/main.go	Updated tracer initialization to use new otel package with configuration from environment variables
server/internal/app/app.go	Modified to conditionally apply OpenTelemetry middleware based on configuration
server/internal/app/server.go	Added service name differentiation for main API vs internal API traces
server/internal/app/tracer.go	Removed legacy GCP and Jaeger tracer initialization code
server/go.mod, server/go.sum	Updated OpenTelemetry dependencies to v1.38.0 and added OTLP exporter packages

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[wilfredmulenga]

Looks good