Phase 2: EVE SSO auth + read-only account tools

Add PKCE OAuth2 login against EVE SSO with an encrypted, auto-refreshing
token store, driven by `familiar login` / `status` / `logout` CLI commands.
The MCP server gains authenticated account tools:

- account_status, get_wallet, get_skills, get_skill_queue
- get_location, get_clones, get_assets (paginated)

ESI client extended with Bearer auth and X-Pages pagination. 51 tests
(auth + account mocked), coverage 88%. Client id/callback/scopes are
env-overridable; refresh token Fernet-encrypted on disk.

Closes #7

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

tests/test_auth.py

@@ -0,0 +1,126 @@
+"""EVE SSO auth: PKCE, JWT claims, token store, exchange/refresh, get_auth."""
+
+import asyncio
+import base64
+import hashlib
+
+import httpx
+import pytest
+
+from conftest import make_jwt
+from familiar import auth
+
+
+@pytest.fixture
+def tmp_store(tmp_path, monkeypatch):
+    """Point the token/key files at a temp dir."""
+    monkeypatch.setenv("FAMILIAR_DATA_DIR", str(tmp_path))
+    return tmp_path
+
+
+def test_generate_pkce_challenge_matches_verifier():
+    verifier, challenge = auth.generate_pkce()
+    expected = (
+        base64.urlsafe_b64encode(hashlib.sha256(verifier.encode()).digest()).rstrip(b"=").decode()
+    )
+    assert challenge == expected
+    assert "=" not in challenge
+
+
+def test_build_authorize_url_has_required_params():
+    url = auth.build_authorize_url("the-state", "the-challenge")
+    assert "response_type=code" in url
+    assert "code_challenge=the-challenge" in url
+    assert "code_challenge_method=S256" in url
+    assert "state=the-state" in url
+    assert "client_id=" in url
+
+
+def test_decode_jwt_and_character_id():
+    token = make_jwt({"sub": "CHARACTER:EVE:2112000001", "name": "Latte", "scp": ["a"]})
+    claims = auth.decode_jwt_claims(token)
+    assert claims["name"] == "Latte"
+    assert auth.character_id_from_claims(claims) == 2112000001
+
+
+def test_character_id_from_bad_sub_raises():
+    with pytest.raises(auth.AuthError):
+        auth.character_id_from_claims({"sub": "nonsense"})
+
+
+def test_decode_malformed_token_raises():
+    with pytest.raises(auth.AuthError):
+        auth.decode_jwt_claims("not-a-jwt")
+
+
+def test_token_store_round_trip(tmp_store):
+    bundle = {"refresh_token": "r", "character_id": 7, "character_name": "X"}
+    assert auth.load_tokens() is None
+    auth.save_tokens(bundle)
+    assert auth.load_tokens() == bundle
+    assert (tmp_store / "token.enc").exists()
+    assert auth.clear_tokens() is True
+    assert auth.load_tokens() is None
+    assert auth.clear_tokens() is False
+
+
+def test_stored_token_is_encrypted_not_plaintext(tmp_store):
+    auth.save_tokens({"refresh_token": "super-secret-value", "character_id": 1})
+    raw = (tmp_store / "token.enc").read_bytes()
+    assert b"super-secret-value" not in raw
+
+
+def _token_transport(payload):
+    return httpx.MockTransport(lambda req: httpx.Response(200, json=payload))
+
+
+def test_exchange_code_posts_and_parses():
+    payload = {"access_token": "a", "refresh_token": "r", "expires_in": 1200}
+    out = asyncio.run(auth.exchange_code("code", "verifier", transport=_token_transport(payload)))
+    assert out["refresh_token"] == "r"
+
+
+def test_token_request_raises_on_error():
+    transport = httpx.MockTransport(lambda req: httpx.Response(400, text="bad_request"))
+    with pytest.raises(auth.AuthError):
+        asyncio.run(auth.refresh_tokens("r", transport=transport))
+
+
+def test_get_auth_without_login_raises(tmp_store):
+    with pytest.raises(auth.NotAuthenticated):
+        asyncio.run(auth.get_auth())
+
+
+def test_get_auth_uses_unexpired_token(tmp_store):
+    auth.save_tokens(
+        {
+            "access_token": "still-good",
+            "refresh_token": "r",
+            "character_id": 9,
+            "expires_at": 10_000,
+        }
+    )
+    token, cid = asyncio.run(auth.get_auth(now=5_000))
+    assert token == "still-good"
+    assert cid == 9
+
+
+def test_get_auth_refreshes_when_expired(tmp_store):
+    auth.save_tokens(
+        {"access_token": "old", "refresh_token": "r0", "character_id": 9, "expires_at": 1_000}
+    )
+    new_access = make_jwt({"sub": "CHARACTER:EVE:9", "name": "Latte"})
+    payload = {"access_token": new_access, "refresh_token": "r1", "expires_in": 1200}
+    token, cid = asyncio.run(auth.get_auth(now=2_000, transport=_token_transport(payload)))
+    assert token == new_access
+    assert cid == 9
+    # The rotated refresh token is persisted.
+    assert auth.load_tokens()["refresh_token"] == "r1"
+
+
+def test_status_reflects_store(tmp_store):
+    assert auth.status() == {"authenticated": False}
+    auth.save_tokens({"refresh_token": "r", "character_id": 3, "character_name": "Y", "scopes": []})
+    info = auth.status()
+    assert info["authenticated"] is True
+    assert info["character_id"] == 3