Phase 1: public market + universe lookups via ESI

Add a thin async ESI client (httpx, descriptive User-Agent, uniform errors,
mockable transport) plus name<->id resolution. New read-only tools:

- universe: resolve_names, get_item, get_system, get_station, get_region, get_route
- market:   list_hubs, get_market_price, get_market_orders, compare_hubs

Trade-hub IDs (Jita/Amarr/Dodixie/Rens/Hek) are hardcoded constants. Market
aggregation (best buy/sell, spread, order book) lives in pure helpers. 30 unit
tests with mocked ESI; coverage 99%. SDE bulk-load deferred to a later phase.

Closes #2

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

tests/test_market.py

@@ -0,0 +1,128 @@
+"""Market lookup tools and pure aggregation helpers."""
+
+import asyncio
+
+import pytest
+
+from familiar import hubs, market
+from familiar.server import mcp
+from conftest import route
+
+JITA_STATION = 60003760
+JITA_REGION = 10000002
+
+
+def _orders():
+    return [
+        # Sells at Jita
+        {
+            "is_buy_order": False,
+            "location_id": JITA_STATION,
+            "price": 5.10,
+            "volume_remain": 100,
+            "range": "station",
+        },
+        {
+            "is_buy_order": False,
+            "location_id": JITA_STATION,
+            "price": 5.05,
+            "volume_remain": 200,
+            "range": "station",
+        },
+        # Buy at Jita
+        {
+            "is_buy_order": True,
+            "location_id": JITA_STATION,
+            "price": 4.90,
+            "volume_remain": 300,
+            "range": "region",
+        },
+        # Order at a different station should be ignored
+        {
+            "is_buy_order": False,
+            "location_id": 999,
+            "price": 1.0,
+            "volume_remain": 1,
+            "range": "station",
+        },
+    ]
+
+
+def test_summarize_orders_picks_best_and_ignores_other_stations():
+    s = market.summarize_orders(_orders(), JITA_STATION)
+    assert s["best_sell"] == 5.05
+    assert s["best_buy"] == 4.90
+    assert s["spread"] == 0.15
+    assert s["sell_orders"] == 2
+    assert s["volume_on_sell"] == 300
+
+
+def test_summarize_orders_handles_empty():
+    s = market.summarize_orders([], JITA_STATION)
+    assert s["best_sell"] is None
+    assert s["spread"] is None
+
+
+def test_top_orders_sorts_per_side():
+    sells = market.top_orders(_orders(), JITA_STATION, "sell", 10)
+    assert [o["price"] for o in sells] == [5.05, 5.10]
+    buys = market.top_orders(_orders(), JITA_STATION, "buy", 10)
+    assert [o["price"] for o in buys] == [4.90]
+
+
+def test_get_market_price(mock_esi):
+    fixtures = {
+        "/universe/ids/": {"inventory_types": [{"id": 34, "name": "Tritanium"}]},
+        f"/markets/{JITA_REGION}/orders/": _orders(),
+    }
+    mock_esi(lambda req: route(req, fixtures))
+    result = asyncio.run(market.get_market_price("Tritanium", hub="Jita"))
+    assert result["type_id"] == 34
+    assert result["hub"] == "Jita"
+    assert result["best_sell"] == 5.05
+
+
+def test_get_market_orders_side_parsing(mock_esi):
+    fixtures = {f"/markets/{JITA_REGION}/orders/": _orders()}
+    mock_esi(lambda req: route(req, fixtures))
+    result = asyncio.run(market.get_market_orders(34, hub="Jita", side="buy", limit=5))
+    assert result["side"] == "buy"
+    assert result["orders"][0]["price"] == 4.90
+
+
+def test_compare_hubs_across_all_regions(mock_esi):
+    # Every region returns the same order book; cheapest sell is the same price
+    # everywhere, so the first hub (Jita) wins the tie.
+    def handler(req):
+        return route(
+            req,
+            {
+                "/orders/": _orders(),
+                "/universe/ids/": {"inventory_types": [{"id": 34, "name": "Tritanium"}]},
+            },
+        )
+
+    mock_esi(handler)
+    result = asyncio.run(market.compare_hubs("Tritanium"))
+    assert len(result["hubs"]) == len(hubs.HUBS)
+    assert result["cheapest_sell_hub"] == "Jita"
+
+
+def test_list_hubs():
+    result = asyncio.run(market.list_hubs())
+    names = {h["name"] for h in result}
+    assert {"Jita", "Amarr", "Dodixie", "Rens", "Hek"} == names
+
+
+def test_resolve_hub_unknown_raises():
+    with pytest.raises(ValueError):
+        hubs.resolve_hub("Atlantis")
+
+
+def test_resolve_hub_defaults_to_jita():
+    assert hubs.resolve_hub(None).name == "Jita"
+
+
+def test_market_tools_are_registered():
+    tools = {t.name for t in asyncio.run(mcp.list_tools())}
+    assert {"list_hubs", "get_market_price", "get_market_orders", "compare_hubs"} <= tools