#1716 Generic OTLP endpoint appends signal path after query or fragment

Problem

Generic OTLP endpoint construction appends /v1/ to the raw environment-variable string. An endpoint such as https://collector.example/otlp?token=[REDACTED-SECRET-1] becomes https://collector.example/otlp?token=[REDACTED-SECRET-2] so the signal suffix lands in the query instead of the URL path. Fragments have the same problem.

Current implementation

src/infrastructure/tracing/otel_config.ts uses string concatenation after trimming trailing slashes.

Expected behavior

Append the signal suffix to the URL pathname while preserving query and fragment components. Add endpoint-resolution tests for query and fragment inputs.

This is pre-existing generic endpoint behavior and is separate from Lab issue 1713, which intentionally preserves current generic fallback semantics.