Fix onboarding modal showing for paid users

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Summary

This PR fixes an issue where paid users were seeing the onboarding dialog at the end of every request, even after they had purchased credits.

Changes

• Updated isOutOfStarterCredits function in core/llm/utils/starterCredits.ts to check optedInToFreeTrial status
• Added comprehensive test coverage for various user scenarios (free trial, paid users with/without credits, etc.)

Problem

The previous logic only checked if users:

1. Were using credits-based API keys
2. Had no credits remaining
3. Had not purchased credits

However, this didn't properly distinguish between:

• Free trial users who never opted in (should not see dialog)
• Paid users who exhausted their purchased credits (should not see dialog)
• Free trial users who opted in and ran out of credits (should see dialog)

Solution

Now the function checks all four conditions:

1. Using credits-based API key
2. Opted into free trial
3. No credits remaining
4. Has not purchased credits

This ensures only free trial users who have exhausted their trial credits will see the onboarding modal.

Fixes CON-4405

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This agent session was co-authored by nate and Continue.

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Summary by cubic

Fixes the onboarding modal showing for paid users after they run out of purchased credits. The modal now only appears for free-trial users who opted in, are using a credits-based key, have no credits, and haven’t purchased credits. Fixes CON-4405.

• Bug Fixes
  • Updated isOutOfStarterCredits to require optedInToFreeTrial and no purchased credits.
  • Added tests for free trial, paid, and non-credits key scenarios.