Add OpenTelemetry trace-log correlation evidence gates

[DENGXUELIN]

Summary

• Adds an OpenTelemetry trace-log correlation evidence gate to log-analysis with checks for TraceId/SpanId, TraceFlags, sampling, resource context, vendor-field mapping, semantic attributes, join validation, timing, and confidence.
• Extends the output template with an OpenTelemetry correlation evidence table.
• Adds vulnerable and benign fixtures for request-ID-only correlation versus validated trace-log joins.

Bounty

Addresses #1696 as an Improver contribution.

Validation

• git diff --cached --check
• Markdown fence-balance check over staged .md files
• Added-line ASCII check
• Required marker check for OTEL-CORR-01 through OTEL-CORR-08
• Added-line secret-pattern scan
• git diff --check origin/main...HEAD
• git merge-tree --write-tree origin/main HEAD