feat: add tool_modules parameter for selective built-in module loading

[MiteshSoni01]

Purpose

Add a tool_modules parameter to ROSATools and ROSA that allows selective loading of built-in tool modules. This enables purpose-built agents to disable unused ROS introspection tools, significantly reducing prompt token overhead.

Proposed Changes

• [ADD] tool_modules parameter to ROSATools.__init__ with full docstring, ALL_MODULES/DEFAULT_MODULES constants, selective module loading logic, and UserWarning for unknown module names
• [ADD] tool_modules parameter to ROSA.__init__ and _get_tools() with updated class docstring and usage examples
• [ADD] Set to typing imports in rosa.py
• [ADD] Restored and updated _get_tools() docstring with new parameter documented
• [ADD] TestROSAToolModules test class with 6 tests covering: empty set, None default, selective loading, unknown module warning, default behaviour, and custom tools with empty modules

Issues

No existing issue - proposing new feature based on real-world deployment need.

Testing

All 6 new tests pass on ROS1 Noetic, Python 3.10.14, Jetson Orin NX hardware:

• TestROSAToolModules::test_custom_tools_work_with_empty_tool_modules PASSED
• TestROSAToolModules::test_empty_tool_modules_loads_no_builtin_tools PASSED
• TestROSAToolModules::test_none_tool_modules_loads_all_builtin_tools PASSED
• TestROSAToolModules::test_selective_tool_modules_loads_only_specified PASSED
• TestROSAToolModules::test_tool_modules_defaults_to_all PASSED
• TestROSAToolModules::test_unknown_module_raises_warning PASSED

Note: TestROSATools::test_adds_default_tools fails on the upstream main branch before our changes - confirmed pre-existing issue unrelated to this PR.

Real-world impact: Tested on ROS1 Noetic on Jetson Orin NX hardware. Disabling unused built-in modules reduced prompt tokens by 50-78% per query (from ~10,000 to ~2,400-4,800 tokens), significantly reducing latency and API cost for production deployments.

Usage:

Disable all built-in tools - use only custom tools

agent = ROSA(ros_version=1, llm=llm, tool_packages=[my_tools], tool_modules=set())

Load only specific built-in modules

agent = ROSA(ros_version=1, llm=llm, tool_modules={"calculation", "system"})

Default behaviour unchanged

agent = ROSA(ros_version=1, llm=llm)

Backwards compatible: tool_modules=None (default) preserves existing behaviour exactly.