Add Phase 1A-C + ICE warehouse stocks: prices, methodology, pipeline automation

Phase 1A — KC=F Coffee Futures Prices:
- New extract/coffee_prices/ package (yfinance): downloads KC=F daily OHLCV,
  stores as gzip CSV with SHA256-based idempotency
- SQLMesh models: raw/coffee_prices → foundation/fct_coffee_prices →
  serving/coffee_prices (with 20d/50d SMA, 52-week high/low, daily return %)
- Dashboard: 4 metric cards + dual-line chart (close, 20d MA, 50d MA)
- API: GET /commodities/<ticker>/prices

Phase 1B — Data Methodology Page:
- New /methodology route with full-page template (base.html)
- 6 anchored sections: USDA PSD, CFTC COT, KC=F price, ICE warehouse stocks,
  data quality model, update schedule table
- "Methodology" link added to marketing footer

Phase 1C — Automated Pipeline:
- supervisor.sh updated: runs extract_cot, extract_prices, extract_ice in
  sequence before transform
- Webhook failure alerting via ALERT_WEBHOOK_URL env var (ntfy/Slack/Telegram)

ICE Warehouse Stocks:
- New extract/ice_stocks/ package (niquests): normalizes ICE Report Center CSV
  to canonical schema, hash-based idempotency, soft-fail on 404 with guidance
- SQLMesh models: raw/ice_warehouse_stocks → foundation/fct_ice_warehouse_stocks
  → serving/ice_warehouse_stocks (30d avg, WoW change, 52w drawdown)
- Dashboard: 4 metric cards + line chart (certified bags + 30d avg)
- API: GET /commodities/<code>/stocks

Foundation:
- dim_commodity: added ticker (KC=F) and ice_stock_report_code (COFFEE-C) columns
- macros/__init__.py: added prices_glob() and ice_stocks_glob()
- pipelines.py: added extract_prices and extract_ice entries

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

transform/sqlmesh_materia/models/raw/coffee_prices.sql

@@ -0,0 +1,46 @@
+-- Raw KC=F Coffee C futures prices — technical ingestion layer.
+--
+-- Reads daily OHLCV gzip CSVs from the landing directory. All values are
+-- varchar; casting happens in foundation.fct_coffee_prices.
+--
+-- Source: Yahoo Finance via yfinance (KC=F ticker)
+-- Coverage: 1971-present (historical futures data)
+-- Frequency: daily (trading days only)
+
+MODEL (
+  name raw.coffee_prices,
+  kind FULL,
+  grain (Date),
+  cron '@daily',
+  columns (
+    Date        varchar,
+    Open        varchar,
+    High        varchar,
+    Low         varchar,
+    Close       varchar,
+    Adj_Close   varchar,
+    Volume      varchar,
+    filename    varchar
+  )
+);
+
+SELECT
+  "Date"      AS Date,
+  "Open"      AS Open,
+  "High"      AS High,
+  "Low"       AS Low,
+  "Close"     AS Close,
+  "Adj Close" AS Adj_Close,
+  "Volume"    AS Volume,
+  filename
+FROM read_csv(
+  @prices_glob(),
+  delim = ',',
+  encoding = 'utf-8',
+  compression = 'gzip',
+  header = true,
+  union_by_name = true,
+  filename = true,
+  all_varchar = true,
+  ignore_errors = true
+)

transform/sqlmesh_materia/models/raw/ice_warehouse_stocks.sql

@@ -0,0 +1,37 @@
+-- Raw ICE certified warehouse stocks — technical ingestion layer.
+--
+-- Reads daily stock report gzip CSVs from the landing directory.
+-- All values are varchar; casting happens in foundation.fct_ice_warehouse_stocks.
+--
+-- Source: ICE Report Center (Coffee C certified warehouse stocks)
+-- Coverage: varies by download history
+-- Frequency: daily (ICE updates after market close)
+
+MODEL (
+  name raw.ice_warehouse_stocks,
+  kind FULL,
+  cron '@daily',
+  columns (
+    report_date             varchar,
+    total_certified_bags    varchar,
+    pending_grading_bags    varchar,
+    filename                varchar
+  )
+);
+
+SELECT
+  report_date,
+  total_certified_bags,
+  pending_grading_bags,
+  filename
+FROM read_csv(
+  @ice_stocks_glob(),
+  delim = ',',
+  encoding = 'utf-8',
+  compression = 'gzip',
+  header = true,
+  union_by_name = true,
+  filename = true,
+  all_varchar = true,
+  ignore_errors = true
+)