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)

config/data_config.yaml

@@ -93,4 +93,12 @@ data_center:
 
 bitcoin:
   hashrate_range: [150, 250]  # EH/s
-  mining_efficiency_range: [25, 35]  # J/TH
+  power_efficiency_range: [80, 120]  # TH/s per MW
+  eur_usd_rate: 0.92  # For converting to EUR base price
+
+transmission:
+  capacity_base_range: [1000, 4000]  # MW
+  capacity_uk_multiplier: 0.6  # UK connections typically lower
+  efficiency_range: [0.95, 0.99]
+  congestion_surcharge_range: [0.5, 5.0]  # EUR/MWh
+  fee_range: [0, 2.0]  # EUR/MWh