feat(backend): Add cable graph service and data collectors

## Changelog

### New Features

#### Cable Graph Service
- Add cable_graph.py for finding shortest path between landing points
- Implement haversine distance calculation for great circle distances
- Support for dateline crossing (longitude normalization)
- NetworkX-based graph for optimal path finding

#### Data Collectors
- Add ArcGISCableCollector for fetching submarine cable data from ArcGIS GeoJSON API
- Add FAOLandingPointCollector for fetching landing point data from FAO CSV API

### Backend Changes

#### API Updates
- auth.py: Update authentication logic
- datasources.py: Add datasource endpoints and management
- visualization.py: Add visualization API endpoints
- config.py: Update configuration settings
- security.py: Improve security settings

#### Models & Schemas
- task.py: Update task model with new fields
- token.py: Update token schema

#### Services
- collectors/base.py: Improve base collector with better error handling
- collectors/__init__.py: Register new collectors
- scheduler.py: Update scheduler logic
- tasks/scheduler.py: Add task scheduling

### Frontend Changes
- AppLayout.tsx: Improve layout component
- index.css: Add global styles
- DataSources.tsx: Enhance data sources management page
- vite.config.ts: Add Vite configuration for earth module

backend/app/services/collectors/fao_landing.py

@@ -0,0 +1,66 @@
+"""FAO Landing Points Collector
+
+Collects landing point data from FAO CSV API.
+"""
+
+from typing import Dict, Any, List
+from datetime import datetime
+import httpx
+
+from app.services.collectors.base import BaseCollector
+
+
+class FAOLandingPointCollector(BaseCollector):
+    name = "fao_landing_points"
+    priority = "P1"
+    module = "L2"
+    frequency_hours = 168
+    data_type = "landing_point"
+
+    csv_url = "https://data.apps.fao.org/catalog/dataset/1b75ff21-92f2-4b96-9b7b-98e8aa65ad5d/resource/b6071077-d1d4-4e97-aa00-42e902847c87/download/landing-point-geo.csv"
+
+    async def fetch(self) -> List[Dict[str, Any]]:
+        async with httpx.AsyncClient(timeout=60.0) as client:
+            response = await client.get(self.csv_url)
+            response.raise_for_status()
+            return self.parse_csv(response.text)
+
+    def parse_csv(self, csv_text: str) -> List[Dict[str, Any]]:
+        result = []
+
+        lines = csv_text.strip().split("\n")
+        if not lines:
+            return result
+
+        for line in lines[1:]:
+            if not line.strip():
+                continue
+            parts = line.split(",")
+            if len(parts) >= 4:
+                try:
+                    lon = float(parts[0])
+                    lat = float(parts[1])
+                    feature_id = parts[2]
+                    name = parts[3].strip('"')
+                    is_tbd = parts[4].strip() == "true" if len(parts) > 4 else False
+
+                    entry = {
+                        "source_id": f"fao_lp_{feature_id}",
+                        "name": name,
+                        "country": "",
+                        "city": "",
+                        "latitude": str(lat),
+                        "longitude": str(lon),
+                        "value": "",
+                        "unit": "",
+                        "metadata": {
+                            "is_tbd": is_tbd,
+                            "original_id": feature_id,
+                        },
+                        "reference_date": datetime.utcnow().strftime("%Y-%m-%d"),
+                    }
+                    result.append(entry)
+                except (ValueError, IndexError):
+                    continue
+
+        return result