Support Python-formatted tool calls from LFM2-8B-A1B

[atdrendel]

• Support Python-formatted tool calls from LFM2-8B-A1B
• Expose Python.parseFunctionCall
• Add tools parameter to LLM.init() and convenience factory methods

[Copilot]

Pull Request Overview

This PR adds support for Python-formatted tool calls from the LFM2-8B-A1B model by introducing a custom response parser that handles Python-style function call syntax. The implementation includes a new Python.parseFunctionCall method for parsing tool invocations and exposes a tools parameter across all LLM factory methods.

Key changes:

• Implemented Python-style function call parser with comprehensive test coverage
• Added LFM2-specific response parser with streaming tool call support
• Extended all LLM factory methods to accept a tools parameter

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Tests/SHLLMTests/PythonTests.swift	Comprehensive tests for Python function call parsing covering edge cases like quotes, escapes, and incremental parsing
Tests/SHLLMTests/Models/LFM2-8B-A1BTests.swift	Integration tests validating LFM2 tool calling with weather, stock, and news tools
Tests/SHLLMTests/Models/GPTOSS-20BTests.swift	Removed assertion checking for "alex" in response
Tests/SHLLMTests/LFM2ParserTests.swift	Unit tests for LFM2 response parser handling tool call tokens and streaming
Tests/SHLLMTests/Helpers.swift	Enhanced web search tool description
Sources/SHLLM/SHLLM.swift	Exported ToolSpec typealias
Sources/SHLLM/ResponseParser.swift	Implemented LFM2 response parser with Python-style tool call handling
Sources/SHLLM/Python.swift	Core Python function call parser implementation
Sources/SHLLM/LLM.swift	Added tools parameter to all factory methods and updated initialization logic

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