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_lookup.py

@@ -0,0 +1,37 @@
+"""Name <-> id resolution."""
+
+import asyncio
+
+import httpx
+import pytest
+
+from familiar import lookup
+
+
+def test_resolve_id_passes_through_numeric():
+    assert asyncio.run(lookup.resolve_id(34)) == 34
+    assert asyncio.run(lookup.resolve_id("34")) == 34
+
+
+def test_resolve_name_picks_requested_category(mock_esi):
+    body = {
+        "inventory_types": [{"id": 34, "name": "Tritanium"}],
+        "systems": [{"id": 30000142, "name": "Jita"}],
+    }
+    mock_esi(lambda req: httpx.Response(200, json=body))
+    assert asyncio.run(lookup.resolve_name("Tritanium", "inventory_types")) == (
+        34,
+        "inventory_types",
+    )
+
+
+def test_resolve_id_resolves_name(mock_esi):
+    body = {"inventory_types": [{"id": 34, "name": "Tritanium"}]}
+    mock_esi(lambda req: httpx.Response(200, json=body))
+    assert asyncio.run(lookup.resolve_id("Tritanium", "inventory_types")) == 34
+
+
+def test_resolve_name_raises_when_absent(mock_esi):
+    mock_esi(lambda req: httpx.Response(200, json={}))
+    with pytest.raises(LookupError):
+        asyncio.run(lookup.resolve_name("Nope", "inventory_types"))