feat: support propagation of OpenTelemetry context from clients

[pdecat]

This PR allows forwarding OpenTelemetry context from clients to Steampipe FDW.

From client perspective, it can be used like this (python with psycopg):

import logging

import psycopg

from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator

logger = logging.getLogger(__name__)

steampipe_conn = psycopg.connect(
    host="127.0.0.1",
    dbname="steampipe",
    user="steampipe",
    port="9193",
    password="steampipe",
    autocommit=True,
)

trace_context = {}
TraceContextTextMapPropagator().inject(trace_context)
if traceparent := trace_context.get("traceparent"):
    logger.debug("Propagating OpenTelemetry traceparent: %s", traceparent)
    steampipe_conn.execute(f"SET steampipe.traceparent = '{traceparent}'")

    if tracestate := trace_context.get("tracestate"):
        logger.debug("Propagating OpenTelemetry tracestate=%s", tracestate)
        steampipe_conn.execute(f"SET steampipe.tracestate = '{tracestate}'")

steampipe_conn.execute("SELECT account_id FROM aws_account")
steampipe_conn.execute("SELECT arn FROM aws_health_event")

When traces are ingested in an OpenTelemetry compatible solution such as Google Cloud Tracing, traces are properly grouped, e.g.:

[Copilot]

Pull Request Overview

This PR enables the propagation of OpenTelemetry context from clients to Steampipe FDW by extracting and forwarding tracing information.

• Adds new functions and tests to parse and propagate trace context in hub and FDW layers.
• Updates function signatures and logging for better trace context handling and debugging.
• Integrates trace context extraction from PostgreSQL session variables into the FDW plan state.

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
types/pathkeys_test.go	Removed an unnecessary blank line.
hub/trace_context_test.go	Introduced tests for tracing context parsing and verification.
hub/scan_iterator_base.go	Added debug logging for creating and validating trace carriers.
hub/hub_remote.go & hub/hub_local.go	Updated trace context function calls to incorporate new options.
hub/hub_base.go	Modified trace context propagation and parsing, with improved logging.
fdw/fdw_helpers.h, fdw/fdw.c, fdw/common.h, fdw.go	Added functions to extract and integrate trace context from session variables.

Comments suppressed due to low confidence (1)

hub/hub_base.go:434

• The 'strings' package is used in parseTraceContext but is not imported. Please add "import "strings"" to the import block.

	parts := strings.Split(traceContextString, ";")

[pdecat]

Also done separately in #567

[pdecat]

I need to fix indentation...