Fix filtering and add clustering for large-scale environments

[Claude]

Two open issues reported filter limitations and performance problems with 1000+ locations.

Issue #13: Enhanced Filtering

Added Status and Parent filters to complement existing Type and Tenant filters. All filters now work correctly together:

// Filter logic applies all constraints with AND semantics
const filtered = allLocations.filter((loc) => {
  if (statusVal && loc.status !== statusVal) return false;
  if (typeVal && loc.location_type !== typeVal) return false;
  if (parentVal && loc.parent !== parentVal) return false;
  if (tenantVal && loc.tenant !== tenantVal) return false;
  return true;
});

• Status filter: Active, Planned, Other (matches legend)
• Parent filter: Hierarchical location filtering
• Clear Filters button: Reset all filters at once

Issue #14: Performance Optimization

Implemented grid-based marker clustering for environments with 100+ locations:

const CLUSTER_THRESHOLD = 100;
const gridSize = currentZoom < 5 ? 2 : currentZoom < 8 ? 1 : 0.5;

// Group markers by grid cells at current zoom level
const clusters = {};
for (const loc of locations) {
  const key = `${Math.floor(loc.latitude / gridSize)},${Math.floor(loc.longitude / gridSize)}`;
  if (!clusters[key]) clusters[key] = [];
  clusters[key].push(loc);
}

• Zoom-adaptive grid sizing: coarser at low zoom, finer at high zoom
• Interactive cluster markers show location count and list
• Click clusters to zoom in and reveal individual markers
• Automatic re-clustering on zoom events
• Progressive loading indicators with status messages

Zero external dependencies. No breaking changes. All 63 tests pass.

Original prompt

look in to the issues