Show source location (city/state/zip) in list_sources output

/api/data/sources now returns per-source geo; surface it as a Location column
in the sources table.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_format.py

@@ -200,12 +200,14 @@ def test_fmt_basis_detail_per_series():
 def test_fmt_sources_table():
     payload = {"sources": [
         {"id": 1, "name": "Test Elev", "kind": "elevator",
+         "city": "Ada", "state": "OH", "zip": "45810",
          "last_success_at": "2026-05-20T14:55:00+00:00",
          "consecutive_failures": 0, "last_error": None},
     ]}
     out = fmt.fmt_sources(payload)
     assert "Test Elev" in out
     assert "elevator" in out
+    assert "Ada, OH 45810" in out   # location column
 
 
 def test_fmt_health_buckets():