🎚️ feat: Add Thinking Level Parameter for Gemini 3+ Models (#11994)

* 🧠 feat: Add Thinking Level Config for Gemini 3 Models

- Introduced a new setting for 'thinking level' in the Google configuration, allowing users to control the depth of reasoning for Gemini 3 models.
- Updated translation files to include the new 'thinking level' label and description.
- Enhanced the Google LLM configuration to support the new 'thinking level' parameter, ensuring compatibility with both Google and Vertex AI providers.
- Added necessary schema and type definitions to accommodate the new setting across the data provider and API layers.

* test: Google LLM Configuration for Gemini 3 Models

- Added tests to validate default thinking configuration for Gemini 3 models, ensuring `thinkingConfig` is set correctly without `thinkingLevel`.
- Implemented logic to ignore `thinkingBudget` for Gemini 3+ models, confirming that it does not affect the configuration.
- Included a test to verify that `gemini-2.9-flash` is not classified as a Gemini 3+ model, maintaining expected behavior for earlier versions.
- Updated existing tests to ensure comprehensive coverage of the new configurations and behaviors.

* fix: Update translation for Google LLM thinking settings

- Revised descriptions for 'thinking budget' and 'thinking level' in the English translation file to clarify their applicability to different Gemini model versions.
- Ensured that the new descriptions accurately reflect the functionality and usage of the settings for Gemini 2.5 and 3 models.

* docs: Update comments for Gemini 3+ thinking configuration

- Added detailed comments in the Google LLM configuration to clarify the differences between `thinkingLevel` and `thinkingBudget` for Gemini 3+ models.
- Explained the necessity of `includeThoughts` in Vertex AI requests and how it interacts with `thinkingConfig` for improved understanding of the configuration logic.

* fix: Update comment for Gemini 3 model versioning

- Corrected comment in the configuration file to reflect the proper versioning for Gemini models, changing "Gemini 3.0 Models" to "Gemini 3 Models" for clarity and consistency.

* fix: Update thinkingLevel schema for Gemini 3 Models

- Removed nullable option from the thinkingLevel field in the tConversationSchema to ensure it is always defined when present, aligning with the intended configuration for Gemini 3 models.

packages/data-schemas/src/schema/defaults.ts

@@ -83,6 +83,9 @@ export const conversationPreset = {
   thinkingBudget: {
     type: Number,
   },
+  thinkingLevel: {
+    type: String,
+  },
   effort: {
     type: String,
   },