Add transmission datasets and update mining data

Add two new static datasets for cross-region arbitrage calculations:
- transmission_capacity: region-to-region capacity limits (20 rows)
- transmission_cost: transmission costs per path (20 rows)

Update mining dataset with EUR pricing and power metrics:
- Change btc_price_usd to btc_price_eur
- Add power_efficiency_th_per_mw, power_demand_mw
- Add revenue_eur_per_mwh, profit_eur_per_mwh
- Remove mining_profitability column

Changes include:
- scripts/02_fetch_historical.py: rewrite fetch_bitcoin_mining_data()
- scripts/01_generate_synthetic.py: add transmission data generators
- config/data_config.yaml: add transmission config, update bitcoin config
- config/schema.yaml: add 2 new schemas, update bitcoin_mining schema
- scripts/03_process_merge.py: add 2 new datasets
- scripts/04_validate.py: add 2 new datasets
- test/test_data.py: update for new datasets and bitcoin price reference

Total datasets: 9 (734,491 rows, 17.89 MB)

data/metadata/final_metadata.json

@@ -1,7 +1,7 @@
 {
-  "processed_at": "2026-02-10T16:10:49.295018+00:00",
-  "total_datasets": 7,
-  "total_size_mb": 16.977967262268066,
+  "processed_at": "2026-02-10T17:49:27.237574+00:00",
+  "total_datasets": 9,
+  "total_size_mb": 17.2280216217041,
   "datasets": {
     "electricity_prices": {
       "path": "/home/user/energy-test-data/data/processed/electricity_prices.parquet",
@@ -11,19 +11,19 @@
     },
     "battery_capacity": {
       "path": "/home/user/energy-test-data/data/processed/battery_capacity.parquet",
-      "size_mb": 4.204527854919434,
+      "size_mb": 4.204350471496582,
       "rows": 144010,
       "columns": 7
     },
     "renewable_generation": {
       "path": "/home/user/energy-test-data/data/processed/renewable_generation.parquet",
-      "size_mb": 4.482715606689453,
+      "size_mb": 4.483729362487793,
       "rows": 216015,
       "columns": 7
     },
     "conventional_generation": {
       "path": "/home/user/energy-test-data/data/processed/conventional_generation.parquet",
-      "size_mb": 2.749570846557617,
+      "size_mb": 2.7516822814941406,
       "rows": 144010,
       "columns": 6
     },
@@ -35,14 +35,26 @@
     },
     "data_centers": {
       "path": "/home/user/energy-test-data/data/processed/data_centers.parquet",
-      "size_mb": 1.0422554016113281,
+      "size_mb": 1.0423173904418945,
       "rows": 72005,
       "columns": 6
     },
     "bitcoin_mining": {
       "path": "/home/user/energy-test-data/data/processed/bitcoin_mining.parquet",
-      "size_mb": 0.3613767623901367,
+      "size_mb": 0.5998897552490234,
       "rows": 14401,
+      "columns": 9
+    },
+    "transmission_capacity": {
+      "path": "/home/user/energy-test-data/data/processed/transmission_capacity.parquet",
+      "size_mb": 0.0039043426513671875,
+      "rows": 20,
+      "columns": 5
+    },
+    "transmission_cost": {
+      "path": "/home/user/energy-test-data/data/processed/transmission_cost.parquet",
+      "size_mb": 0.004627227783203125,
+      "rows": 20,
       "columns": 6
     }
   }