feat: add explore action for Unitree Go2

[Wanbogang]

Summary

Adds a new explore action that enables the Unitree Go2 robot to autonomously
explore an environment using frontier-based exploration.

Changes

• src/actions/explore/interface.py — defines ExploreInput and Explore interface
• src/actions/explore/connector/unitree_go2_explore.py — connector implementation
• tests/actions/explore/connector/test_unitree_go2_explore.py — full test suite

How It Works

• LLM sends action="explore" to start, action="stop explore" to stop
• On start, the robot captures its current position via UnitreeGo2OdomProvider
• Exploration is managed by UnitreeGo2FrontierExplorationProvider
• On completion (or timeout), the robot optionally returns to its start position
  via UnitreeGo2NavigationProvider
• Voice feedback is provided via ElevenLabsTTSProvider

Parameters

Parameter	Default	Description
action	required	"explore" or "stop explore"
duration	None	Time limit in seconds, None = no limit
return_to_start	True	Return to start position after exploration ends

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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