chore: cherry-pick PM aggregator providers + YAML file tracing to prod

[Flotapponnier]

Cherry-picks 2 commits from dev so the aggregator providers (Mobula, Predexon, Codex) and the file-tracing fix that bundles benchmark YAML files into the Vercel deployment ship to prod openchainbench.com.

Cherry-picked:

• PR feat(pm): aggregator providers (Mobula, Predexon, Codex) on pm-api-latency #606: benchmarks/pm-api-latency.yml gains 6 aggregator provider entries (mobula on Polymarket, predexon on Polymarket plus Kalshi plus Limitless, codex on Polymarket plus Kalshi) and the 5 existing direct providers now filter on source="direct".
• PR fix(build): trace YAML spec dirs so Vercel ships latest dev specs #634: next.config.ts outputFileTracingIncludes so every Vercel build packages the YAML spec dirs (benchmarks, answers, alternatives) rather than reusing a stale snapshot from an earlier prebuilt artifact.

After this lands:

• /benchmarks/pm-api-latency on openchainbench.com shows 11 providers (5 direct + 6 aggregator routes).
• Sample counts per provider stay isolated (no aggregation across sources).