fix(core): preserve existing source properties in claude plugin config

[MaxKless]

Current Behavior

Running configure-ai-agents overwrites the entire source object in extraKnownMarketplaces['nx-claude-plugins'], removing any user-added properties like ref.

Expected Behavior

User-added source properties (e.g. ref) are preserved, while source and repo are always set to the correct values.

🤖 Generated with Claude Code

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☁️ Nx Cloud last updated this comment at 2026-02-19 10:40:59 UTC

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[nx-cloud]

Nx Cloud has identified a possible root cause for your failed CI:

This CI failure appears to be related to the environment or external dependencies rather than your code changes.

No code changes were suggested for this issue.

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