Add solar table migration

Records hourly solar panel readings imported from /home/pmp/ai/solar/csv
by the sibling repo's import-csv.mjs. Schema includes only the 8
columns that always carry data; the 5 always-empty CSV columns are
dropped.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

resources/migrations/20260419000000-create-solar.down.sql

@@ -0,0 +1 @@
+DROP TABLE solar;

resources/migrations/20260419000000-create-solar.up.sql

@@ -0,0 +1,10 @@
+CREATE TABLE solar (
+  period_start       TIMESTAMPTZ      PRIMARY KEY,
+  pv_yield_kwh       DOUBLE PRECISION NOT NULL,
+  inverter_yield_kwh DOUBLE PRECISION NOT NULL,
+  export_kwh         DOUBLE PRECISION NOT NULL,
+  import_kwh         DOUBLE PRECISION NOT NULL,
+  charge_kwh         DOUBLE PRECISION NOT NULL,
+  discharge_kwh      DOUBLE PRECISION NOT NULL,
+  revenue_eur        DOUBLE PRECISION NOT NULL
+);