ICE extraction overhaul: API discovery + aging report + historical backfill

- Replace brittle ICE_STOCKS_URL env var with API-based URL discovery via
  the private ICE Report Center JSON API (no auth required)
- Add rolling CSV → XLS fallback in extract_ice_stocks() using
  find_latest_report() from ice_api.py
- Add ice_api.py: fetch_report_listings(), find_latest_report() with
  pagination up to MAX_API_PAGES
- Add xls_parse.py: detect_file_format() (magic bytes), xls_to_rows()
  using xlrd for OLE2/BIFF XLS files
- Add extract_ice_aging(): monthly certified stock aging report by
  age bucket × port → ice_aging/ landing dir
- Add extract_ice_historical(): 30-year EOM by-port stocks from static
  ICE URL → ice_stocks_by_port/ landing dir
- Add xlrd>=2.0.1 (parse XLS), xlwt>=1.3.0 (dev, test fixtures)
- Add SQLMesh raw + foundation models for both new datasets
- Add ice_aging_glob(), ice_stocks_by_port_glob() macros
- Add extract_ice_aging + extract_ice_historical pipeline entries
- Add 12 unit tests (format detection, XLS roundtrip, API mock, CSV output)

Seed files (data/landing/ice_aging/seed/ and ice_stocks_by_port/seed/)
must be created locally — data/ is gitignored.

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

src/materia/pipelines.py

@@ -28,6 +28,14 @@ PIPELINES = {
         "command": ["uv", "run", "--package", "ice_stocks", "extract_ice"],
         "timeout_seconds": 600,
     },
+    "extract_ice_aging": {
+        "command": ["uv", "run", "--package", "ice_stocks", "extract_ice_aging"],
+        "timeout_seconds": 600,
+    },
+    "extract_ice_historical": {
+        "command": ["uv", "run", "--package", "ice_stocks", "extract_ice_historical"],
+        "timeout_seconds": 600,
+    },
     "transform": {
         "command": ["uv", "run", "--package", "sqlmesh_materia", "sqlmesh", "-p", "transform/sqlmesh_materia", "plan", "prod", "--no-prompts", "--auto-apply"],
         "timeout_seconds": 3600,