fix: recursive flattening for nested error unions

[darshkpatel]

Why

Fixed a bug in the flattenErrorType utility where spreading a flattened union into another union was not working as expected.

What changed

• Fixed the Flatten type in router/errors.ts to properly handle nested unions (again)
• Added a test case that demonstrates spreading a flattened union into another union
• Bumped package version from 0.210.0 to 0.210.1

Versioning

• Breaking protocol change
• Breaking ts/js API change

[darshkpatel]

• fix: recursive flattening for nested error unions #347 👈 (View in Graphite)
• main

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[macroscopeapp]

Fix recursive flattening for nested error unions in errors.Flatten to correct union handling for error schema composition

This change updates the TypeScript type-level flattening logic for error unions and adds a test to cover composing flattened error schemas within nested unions. It also increments the package version and updates the lockfile.

• Modify the errors.Flatten generic type to always recurse into TUnion<Array<infer U>> using Flatten<U>, add a branch to return T when T directly extends TUnion, and export the alias in router/errors.ts
• Add a test case validating acceptance of a flattened base error schema combined with an additional error object via Type.Union in tests/typescript-stress.test.ts
• Bump version from 0.210.0 to 0.210.1 in package.json
• Update generated metadata in package-lock.json

📍Where to Start

Start with the updated errors.Flatten type in router/errors.ts to review the revised recursion and union handling, then verify behavior with the new test in tests/typescript-stress.test.ts.

Changes since #347 opened

• Modified the Flatten generic type alias to remove conditional branch and implement recursive flattening for nested error unions [b139b29]
• Refactored error schema construction in procedure error schema test case [b139b29]

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Macroscope summarized b139b29.

[jackyzha0]