Apply Inflation Layer to Occupany Grid

[vedantgrover]

Description:
Add an inflation layer to expand occupied cells by a certain radius, creating a safety buffer around detected obstacles.

Tasks:

• Implement inflation logic using a configurable inflation_radius parameter.

• Consider a Gaussian or linear decay model for inflation cost.

• Integrate inflation step into the occupancy grid generation pipeline.

Deliverable:
Updated local costmap that includes inflated obstacle areas.