Full cost model: marginal power, labor, profit, live config

Cost model:
- Marginal billing: only charge for watts above idle
- Dedicated billing: charge for all uptime (optional)
- Labor rate: $/hr for operator time, manually logged
- Profit margin: percentage markup on electricity cost
- All parameters adjustable live via POST /config

Dashboard shows:
- Cost breakdown with progress bar
- Power model (idle→load for GPU and system)
- Marginal watts per inference call
- Labor hours + labor cost
- Total owed (electricity + labor + margin)
- GPU utilization, temperature, power draw
- Avg cost per request, estimated remaining requests

Endpoints:
- GET /config — view current cost config
- POST /config — update any parameter live
- GET /stats — full usage stats + cost config (auth required)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.env.example

@@ -1,7 +1,24 @@
 # Mortdecai Gateway Configuration
+# All values can also be adjusted live via POST /config
+
+# Auth
 API_KEY=mk_change_this_to_a_real_key
-GPU_TDP_WATTS=54
-SYSTEM_OVERHEAD_WATTS=30
-ELECTRICITY_RATE=0.15
-SPENDING_CAP=10.00
-ALLOW_MODEL_UPDATES=false
+
+# Power model
+GPU_IDLE_WATTS=15            # GPU at idle (watts)
+GPU_LOAD_WATTS=54            # GPU during inference (watts)
+SYSTEM_IDLE_WATTS=45         # Whole system idle (watts)
+SYSTEM_INFERENCE_WATTS=65    # Whole system during inference (watts)
+
+# Billing
+ELECTRICITY_RATE=0.15        # $/kWh
+BILLING_MODE=marginal        # "marginal" (only extra watts) or "dedicated" (all uptime)
+BASE_RATE_PER_HOUR=0.00      # $/hr base (dedicated mode only)
+SPENDING_CAP=10.00           # $ before gateway stops accepting
+
+# Labor & profit
+LABOR_RATE_PER_HOUR=0.00     # $/hr for setup/maintenance time
+PROFIT_MARGIN=0.00           # Markup multiplier (0.10 = 10%)
+
+# Features
+ALLOW_MODEL_UPDATES=false    # Allow remote model push via /admin/update-model