fix(litellm): detect Gemini models with space-separated names for thought signature injection

[daniel-lxs]

Summary

Fixes the "Corrupted thought signature" error when using LiteLLM with Gemini 3/2.5 models via model groups that use space-separated names (e.g., "Gemini 3 Pro").

Problem

LiteLLM model groups can use space-separated model names like "Gemini 3 Pro" instead of hyphenated names like "gemini-3-pro". The isGeminiModel() function only matched hyphenated names, causing the thought signature injection to be skipped for space-separated names.

When Vertex AI receives a Gemini 3 request without the expected thought signature, it returns:

"Corrupted thought signature." 
"status": "INVALID_ARGUMENT"

Solution

Updated isGeminiModel() to detect both naming conventions:

• Added checks for space-separated patterns: gemini 3, gemini 2.5
• Updated regex to match both hyphens and spaces in provider-prefixed patterns

Changes

• src/api/providers/lite-llm.ts: Updated isGeminiModel() function
• src/api/providers/tests/lite-llm.spec.ts: Added tests for space-separated model names

Testing

All 19 LiteLLM handler tests pass including new tests for:

• "Gemini 3 Pro" (title case with spaces)
• "Gemini 3 Flash" (title case with spaces)
• "gemini 3 pro" (lowercase with spaces)
• "Gemini 2.5 Pro" (Gemini 2.5 variant)
• "google/gemini 3 pro" (provider-prefixed with spaces)
• "vertex_ai/gemini 2.5 pro" (provider-prefixed with spaces)

Closes COM-508

---

Important

Fixes isGeminiModel() in lite-llm.ts to detect Gemini models with space-separated names, adding tests in lite-llm.spec.ts.

• Behavior:
  • Fixes detection of Gemini models with space-separated names in isGeminiModel() in lite-llm.ts.
  • Handles both hyphenated and space-separated naming conventions for Gemini 3 and 2.5 models.
• Testing:
  • Adds tests in lite-llm.spec.ts for space-separated Gemini model names, including provider-prefixed variants.
  • Verifies detection of models like "Gemini 3 Pro", "gemini 3 pro", and "vertex_ai/gemini 2.5 pro".
• Misc:
  • Updates regex in isGeminiModel() to match both hyphens and spaces.

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[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The changes correctly extend isGeminiModel() to detect space-separated Gemini model names from LiteLLM model groups. The implementation follows existing patterns in the codebase and includes comprehensive test coverage. All 19 tests pass.

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[roomote]

Rooviewer   See task on Roo Cloud

Review complete. No issues found.

The changes correctly extend isGeminiModel() to detect space-separated Gemini model names from LiteLLM model groups. The implementation is sound and includes comprehensive test coverage for all variations (title case, lowercase, and provider-prefixed patterns).

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}