feat: add Flop filtering, sorting, and pagination to deployments index
Derive Flop.Schema on Deployment with filterable state/result/garden_name
(via join_fields), sortable state/result/deployed_at/inserted_at. Add
list_flop/1 with garden join. Switch DeploymentLive.Index from mount-based
streaming to handle_params with Flop. Add filter form (garden name search,
state select, result select), sortable column headers, and styled pagination.
Handle Ecto.Enum atom-to-string conversion for filter value retention.
SOW-111
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>