chore: remove unused oaiBuildFunctionInfo helper

[detail-app]

Description

Removes the unused oaiBuildFunctionInfo helper from llm/utils.ts and its re-export from the llm barrel (llm/index.ts). The FunctionCall import in utils.ts is converted to a type-only import since the removed helper was its only runtime consumer.

Changes Made

• Removed oaiBuildFunctionInfo from agents/src/llm/utils.ts
• Removed the oaiBuildFunctionInfo re-export from agents/src/llm/index.ts
• Updated the tracked API report (agents/etc/agents.api.md) to drop the removed symbol
• Switched the FunctionCall import in utils.ts to type FunctionCall (cascading cleanup)

Context

oaiBuildFunctionInfo was marked @internal and had zero callers anywhere — no production code in agents/src, no plugin, no test, and no example referenced it (not even within its own source file). It was an internal helper accidentally leaked through the public barrel. The remaining zero-usage export candidates in the barrel (AsyncToolsetCreateOptions, FallbackAdapterOptions, FormatChatHistoryOptions, ChatContextValidationResult, ChatContextValidationSeverity, OpenAIFunctionParameters, DuplicatePromptArgs, ReplyPromptArgs) were kept because each has a production consumer within its own source file as a param/return/field type of a public API, so removing them would be an export-only removal, which is out of scope.

History

• Last materially changed July 2026 (Agent JS-fication (1.5.0) #1674 @toubatbrian)

Pre-Review Checklist

• Build passes: All builds (lint, typecheck, tests) pass locally
• AI-generated code reviewed: Removed unnecessary comments and ensured code quality
• Changes explained: All changes are properly documented and justified above
• Scope appropriate: All changes relate to the PR title, or explanations provided for why they're included
• Video demo: N/A (dead code removal)

Testing

• Automated tests added/updated (if applicable)
• All tests pass (401 passed, 2 pre-existing skips in src/llm/)
• Make sure both restaurant_agent.ts and realtime_agent.ts work properly (for major changes)

Tooling: Detail: Dead Code

Additional Notes

pnpm api:check was already failing on main before this change due to unrelated pre-existing drift; this change keeps the report consistent with the new source for the removed symbol only.

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Dead Code PRs can be configured here.

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Latest commit: 100eb26

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.