Run the full three-year dispatch and fix issues it surfaced

Executed battery-dispatch run over the full 2018-2020 Attachment 2
series (225.9s, 1096 rolling-horizon windows) and committed the
results: outputs/ (dispatch.csv, annual/monthly summaries, summary.json,
four figures), README.md (setup, run instructions, assumptions, the
one-paragraph approach summary) and RESULTS.md (headline numbers,
per-year table, charts, commentary).

The full run surfaced three real issues, all fixed rather than papered
over:

- validate_schedule's soc_within_bounds check used a fixed 1e-6 MWh
  tolerance for the "state of charge below zero" case, while its
  sibling soc_matches_power_flows check already scales its tolerance
  with sqrt(n) for the same reason (CBC's own solver precision
  accumulating over a long cumulative sum). Over 52,608 half-hours this
  false-failed on a 5.1e-6 MWh solver-noise dip, not a real violation.
  Scaled it the same way.
- cli.py's summary printed net_of_opex_gbp under the label "Less fixed
  opex", so the terminal output showed the post-opex profit (£193k)
  where a reader would expect the opex figure itself (£15k). Split into
  two correctly-labelled lines.
- plots.py's monthly revenue chart stacked Market 1 (always negative
  here) and Market 2 (always positive) with a single running `bottom`,
  which is only correct for same-signed series: Market 2's bar
  completely overlapped and painted over Market 1's, hiding the
  -£297k Market 1 loss entirely. Now accumulates positive and negative
  contributions on separate baselines and marks the net.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

outputs/annual_summary.csv

@@ -0,0 +1,4 @@
+year,gross_profit_gbp,profit_market_1_gbp,profit_market_2_gbp,charged_mwh,discharged_mwh,equivalent_full_cycles,captured_spread_gbp_per_mwh
+2018,67799.45428,-115113.361429,182912.815709,4096.144098,3696.77005,972.834224,18.340187
+2019,64299.710798,-103884.584974,168184.295772,4944.211906,4459.443748,1173.537828,14.418774
+2020,76331.687725,-78420.110711,154751.798435,5561.815889,5022.246341,1321.643774,15.198714

outputs/monthly_summary.csv

@@ -0,0 +1,37 @@
+month,gross_profit_gbp,profit_market_1_gbp,profit_market_2_gbp,charged_mwh,discharged_mwh,equivalent_full_cycles,captured_spread_gbp_per_mwh
+2018-01,5465.302553,-10616.512258,16081.814811,384.869784,343.548311,90.40745,15.908396
+2018-02,5649.230748,-9703.961847,15353.192595,349.200387,318.950019,83.934215,17.711962
+2018-03,8237.234668,-10604.237,18841.471667,396.015555,355.599039,93.578695,23.16439
+2018-04,4806.727348,-9305.278306,14112.005654,360.263313,324.235141,85.325037,14.824819
+2018-05,5511.866602,-9401.571826,14913.438427,370.694857,336.357109,88.515029,16.386948
+2018-06,4846.162293,-8254.164575,13100.326868,344.023224,311.38346,81.943016,15.563326
+2018-07,4733.333558,-10028.827592,14762.16115,352.885749,316.674389,83.335365,14.947005
+2018-08,5369.799211,-10320.611101,15690.410312,325.781443,295.822752,77.848093,18.152083
+2018-09,6294.844593,-8947.096603,15241.941196,306.195008,275.438495,72.483814,22.853903
+2018-10,5998.14371,-7374.223128,13372.366838,305.310416,276.445151,72.748724,21.69741
+2018-11,5658.950526,-9976.708879,15635.659404,308.559422,276.514059,72.766858,20.465327
+2018-12,5227.858471,-10580.168315,15808.026786,292.344937,265.802125,69.947928,19.668234
+2019-01,4846.091122,-9716.467684,14562.558806,301.096315,269.934425,71.035375,17.952846
+2019-02,4386.850007,-9169.974804,13556.824811,354.872114,322.077084,84.757127,13.620497
+2019-03,5685.537534,-9202.12936,14887.666893,395.787504,355.393223,93.524532,15.997878
+2019-04,4718.922967,-9321.77924,14040.702207,366.770343,330.107734,86.870456,14.2951
+2019-05,5427.961092,-9266.13638,14694.097472,424.406564,385.597895,101.47313,14.076739
+2019-06,5106.284583,-8953.112834,14059.397417,431.412168,389.48601,102.496318,13.110316
+2019-07,4410.738629,-10309.250217,14719.988846,455.116658,407.132784,107.140206,10.833661
+2019-08,5371.192114,-7627.944384,12999.136498,411.497847,373.181806,98.205739,14.392963
+2019-09,6108.180331,-6121.834754,12230.015085,446.080294,404.392466,106.41907,15.104585
+2019-10,6225.554888,-7392.268463,13617.823351,460.993925,414.125371,108.980361,15.03302
+2019-11,5546.450256,-9064.889778,14611.340034,417.26031,374.889076,98.65502,14.79491
+2019-12,6465.947275,-7738.797076,14204.744351,478.917865,433.125873,113.980493,14.928564
+2020-01,5752.783129,-6748.3924,12501.175529,469.180307,424.045227,111.590849,13.566438
+2020-02,6045.669316,-5597.409405,11643.07872,446.676521,405.028061,106.586332,14.926544
+2020-03,6146.118796,-6819.499809,12965.618605,494.105284,446.125018,117.401321,13.776674
+2020-04,5671.636666,-5544.659957,11216.296623,482.833775,435.757483,114.673022,13.015581
+2020-05,5591.88205,-5609.8907,11201.77275,518.380706,467.838587,123.115418,11.952588
+2020-06,5305.6492,-5883.53861,11189.18781,491.564836,442.734765,116.509149,11.98381
+2020-07,5152.114341,-6940.203845,12092.318187,513.960584,463.849427,122.065639,11.107299
+2020-08,4740.600521,-9184.278367,13924.878888,479.188819,431.491892,113.550498,10.986534
+2020-09,7591.825678,-6986.500821,14578.326499,397.581913,357.918912,94.189187,21.211021
+2020-10,7291.309946,-7303.097011,14594.406957,443.701444,402.315335,105.872457,18.123371
+2020-11,7836.211148,-5352.907107,13189.118256,436.922129,391.614722,103.056506,20.010001
+2020-12,9205.886933,-6449.732679,15655.619612,387.71957,353.526912,93.033398,26.040131

outputs/summary.json

@@ -0,0 +1,64 @@
+{
+  "solver": {
+    "commit_hours": 24,
+    "degradation_cost_gbp_per_mwh": 0.0,
+    "milp_fallbacks": 1096,
+    "mode": "auto",
+    "window_hours": 48,
+    "windows": 1096
+  },
+  "summary": {
+    "average_captured_spread_gbp_per_mwh": 15.816025,
+    "capacity_end_mwh": 3.861279,
+    "capacity_retained_fraction": 0.96532,
+    "capacity_start_mwh": 4.0,
+    "charged_market_1_mwh": 11297.137749,
+    "charged_market_2_mwh": 3305.034144,
+    "cycle_budget": 5000.0,
+    "cycle_budget_used_fraction": 0.693603,
+    "days": 1096.0,
+    "discharged_market_1_mwh": 1952.341071,
+    "discharged_market_2_mwh": 11226.119067,
+    "end": "2020-12-31 23:30:00",
+    "energy_charged_from_grid_mwh": 14602.171893,
+    "energy_discharged_to_grid_mwh": 13178.460138,
+    "equivalent_full_cycles": 3468.015826,
+    "equivalent_full_cycles_per_year": 1155.741588,
+    "fixed_opex_gbp": 15003.422313,
+    "gross_profit_per_year_gbp": 69461.10309,
+    "gross_trading_profit_gbp": 208430.852803,
+    "half_hours": 52608,
+    "implied_life_years": 4.326227,
+    "net_of_opex_gbp": 193427.430489,
+    "profit_market_1_gbp": -297418.057114,
+    "profit_market_2_gbp": 505848.909916,
+    "profit_share_market_1": -1.426939,
+    "profit_share_market_2": 2.426939,
+    "round_trip_efficiency": 0.9025,
+    "start": "2018-01-01 00:00:00"
+  },
+  "validation": {
+    "checks": {
+      "charge_within_limit": true,
+      "discharge_within_limit": true,
+      "hourly_commitment_constant": true,
+      "no_simultaneous_charge_discharge": true,
+      "revenue_matches_prices_and_powers": true,
+      "soc_matches_power_flows": true,
+      "soc_within_bounds": true
+    },
+    "details": {
+      "hours_checked": 26304.0,
+      "max_hourly_commitment_gap_mw": 0.0,
+      "max_revenue_error_gbp": 0.0,
+      "max_soc_above_capacity_mwh": 0.000413531614,
+      "max_soc_below_zero_mwh": 5.101628e-06,
+      "max_soc_drift_mwh": 5.14322e-06,
+      "max_total_charge_mw": 2.00000005,
+      "max_total_discharge_mw": 2.0000001,
+      "simultaneous_half_hours": 0.0
+    },
+    "failures": [],
+    "ok": true
+  }
+}