feat: add OpenTelemetry-aware scaffolding to new:lambda, new:service and new:domain [DEV-542]

[negarciacamilo]

Description

Scaffolding commands in draft-cli had X-Ray tracing hardcoded across all generated templates, making them incompatible with services already migrated to OpenTelemetry. This PR aligns the scaffolding output with the observability standard established in the api repo: OTEL for new services and domains, and smart auto-detection for lambdas added to existing services.

Task Context

What is the current behavior?

• new:service always generates serverless.yml with X-Ray tracing (tracing: lambda: true), the serverless-plugin-datadog plugin, and no OTEL environment variables or ADOT collector layer.
• new:lambda always generates bootstrap handlers using tracer.BeginSubSegment from framev2/pkg/tracer, regardless of whether the target service uses OTEL or X-Ray.
• new:domain generates service and repository layers with tracer.BeginSubSegment throughout, including repository methods where the DB driver already instruments automatically.
• All select prompts (service list, lambda types, etc.) render in non-deterministic map iteration order.

What is the new behavior?

new:service — always OTEL:

• serverless.yml uses build tag "lambda.norpc,otel", sets tracing: false/false, configures otelFunctionLayers (ADOT collector + DD Extension), and removes serverless-plugin-datadog.
• environment.yml includes all required DD_* and OTEL_* variables.
• Generates config/otel-layer/collector.yaml with the ADOT → Datadog pipeline.
• Initial helloworld lambda includes layers: ${self:custom.otelFunctionLayers} in its lambda-config.yml.

new:lambda — smart detection:

• Reads the target service's serverless.yml and checks for the "lambda.norpc,otel" build tag via project.IsOtelService().
• If OTEL: bootstrap uses oteltracer.StartSpan() with domain/layer attributes and layers in lambda-config.yml.
• If X-Ray: bootstrap uses tracer.BeginSubSegment() (existing behavior preserved).
• Applies to all 6 lambda types: plain, http, sqs, cron, snssqs, custom.

new:domain — always OTEL:

• Service layer uses oteltracer.StartSpan() with ServiceSpanName, Domain, and Layer attributes.
• Repository layer removes all explicit spans — the OTel DB driver instrumentation handles them automatically.
• Applies to both postgres and dynamo variants.

Select prompts:

• All select inputs now sort options alphabetically before rendering, giving a consistent and navigable list.

Additional Context

Adds 29 template syntax tests in internal/templates/templates_test.go that render every template with representative inputs and validate the output using go/parser (Go files) and gopkg.in/yaml.v3 (YAML files). No files are written to disk — all validation happens in memory. Tests cover all lambda types × OTEL/X-Ray, service templates, and domain templates (postgres + dynamo).