#213 Fix: [for cherry-picking] Updated namespace binding to preserve an exis

Fixed Findings

• Preserve enum types across namespace merges

Automated fix from agentic review of https://github.com/metaphorics/bamTiScript/pull/212

Summary by Sourcery

Preserve enum type information across namespace merges while retaining constructor types for standalone namespaces.

Bug Fixes:

• Preserve canonical enum types when same-name namespaces are merged into numeric or string enums.

Tests:

• Add regression coverage verifying numeric and string enum namespace merges retain their enum types.

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Summary by cubic

Preserves enum types when a namespace merges into a numeric or string enum. Previously, the namespace binding overwrote the enum's canonical type with a constructor type; now the enum type is kept, while standalone namespaces still use constructor types.