feat: add NVIDIA NIM provider

[kexiv]

Summary of changes:

• Created src/models/nvidia.js to support NVIDIA NIM API (OpenAI compatible).
• Updated keys.example.json with NVIDIA_API_KEY placeholder.

[kexiv]

Usage Example for andy.json:

{
"name": "andy",
"model": "nvidia/deepseek-ai/deepseek-v3.2"
}

[Copilot]

Pull request overview

This pull request adds support for the NVIDIA NIM provider as an OpenAI-compatible API integration. The implementation follows the established pattern used by other model providers in the codebase, enabling users to interact with NVIDIA's AI models through the same interface as other supported providers.

Changes:

• Added new NVIDIA provider class with OpenAI-compatible API integration
• Updated example configuration file with NVIDIA API key placeholder
• Implemented context length overflow handling with automatic retry logic

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 6 comments.

File	Description
src/models/nvidia.js	New provider class implementing NVIDIA NIM API with sendRequest and embed methods, following the OpenAI-compatible pattern
keys.example.json	Added NVIDIA_API_KEY placeholder and fixed formatting for MERCURY_API_KEY

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[Copilot]

The console log message "Awaiting NVIDIA API" uses uppercase "NVIDIA API" which is inconsistent with other providers. For consistency with deepseek.js:33, mercury.js:40, novita.js:37, and glhf.js:33, this should be lowercase, e.g., "Awaiting nvidia api response..." or "Awaiting NVIDIA api response..." (with lowercase "api").

Suggested change

	console.log(`Awaiting NVIDIA API (${this.model_name}) response...`);
	console.log(`Awaiting nvidia api (${this.model_name}) response...`);

[Copilot]

Missing space after colon in "MERCURY_API_KEY":"". For consistency with other entries in this file (lines 2-17), there should be a space after the colon, i.e., "MERCURY_API_KEY": "".

Suggested change

	"MERCURY_API_KEY":"",
	"NVIDIA_API_KEY":""
	"MERCURY_API_KEY": "",
	"NVIDIA_API_KEY": ""