Description

• Add optional pull-to-zero decay for flow-based area occupancy: when no flow events are
  observed for a configurable idle period, the count is stepped down gradually to compensate
  for missed "out" events that cause counts to drift upward over time
• Refactored findFirst... in AreaOccupancyRepository to return the full entity instead
  of just the count, so the timestamp required for decay calculation is available
• Feature is disabled by default; config keys documented in application.properties

Config

Motivation and Context

How has this been tested?

• Unit tests
• Manual test (on production Valkey stream)

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.