fix(pkg): add default condition to exports for CJS resolvers

[khaliqgant]

Summary

• Add a default condition to both . and ./sdk exports, pointing at the same ESM entry as import.
• Does not change the runtime — package is still type: module and dist is still ESM. This only closes a CJS resolution gap.

Why

The exports map previously declared only types and import conditions:

"exports": {
  ".": {
    "types": "./dist/index.d.ts",
    "import": "./dist/index.js"
  }
}

When a CJS caller — or a tooling path-walker like tsx's resolveTsPaths — lands on this package, Node's CJS resolver picks condition set ['require','node','default'], finds none of them, and errors with ERR_PACKAGE_PATH_NOT_EXPORTED. That surfaced as a confusing "No 'exports' main defined" failure inside agent-relay run's tsx fallback, even though no code was actually trying to require('agent-trajectories').

With default added, the CJS resolver finds a target. If someone really does try to require() the ESM build it will fail with a clear ERR_REQUIRE_ESM, which is the expected ESM-interop error — much better than the misleading "no exports main" message.

The companion fix on AgentWorkforce/relay (#741) removes the tsx fallback in most cases by using node --experimental-strip-types first. This PR is belt-and-suspenders for any other downstream that hits the same resolver path.

Test plan

• npm run build still passes
• npm test still passes
• From a CJS project, require.resolve('agent-trajectories') no longer throws ERR_PACKAGE_PATH_NOT_EXPORTED

🤖 Generated with Claude Code

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[devin-ai-integration]

✅ Devin Review: No Issues Found

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