[OPIK-5658] [FE] fix: align KPI metrics logsSource filter with traces table

[thiagohora]

Details

On the Logs page (Traces tab), the metrics header was showing a trace count that didn't match what the table displayed. When a project had traces from non-SDK sources (e.g. playground, online evaluation), the metrics header counted all traces while the table filtered to SDK-only traces — causing the "Log your first trace" empty state to appear even though the header showed N traces.

The fix adds a logsSource prop to MetricsSummary and threads it through to useProjectKpiCards, which now passes it as an additional filter (alongside existing user filters) to the /kpi-cards endpoint. The TracesSpansTab passes LOGS_SOURCE.sdk so the metrics and table share the same filter scope. The prop is optional so other consumers of MetricsSummary are unaffected.

Change checklist

• User facing
• Documentation update

Issues

• Resolves #
• OPIK-5658

AI-WATERMARK

AI-WATERMARK: yes

• If yes:
  • Tools: Claude Code
  • Model(s): claude-sonnet-4-6
  • Scope: full implementation
  • Human verification: code review + manual reproduction

Testing

• Reproduced locally: project with playground traces shows count > 0 in metrics but "Log your first trace" in table
• After fix: metrics header shows 0 for SDK-only filter, consistent with table
• Verified FilterStrategy.TRACE supports TraceField.SOURCE with ENUM_LEGACY type (includes legacy unknown rows for sdk filter)
• Lint: npm run lint — passed
• Typecheck: pre-existing react-h5-audio-player type error unrelated to this change

Documentation

N/A — internal filter alignment, no user-facing documentation changes required.