feat(server): mint API + Postgres schema + manual adapter (PR 1)

Source-agnostic license issuance service. FastAPI app fronts a
Postgres `licenses` table; the only currently-wired source is
`manual` (operator mints via /internal/mint). Gumroad webhook
adapter lands in PR 2.

Key design points:

- Signing reuses src/license/crypto.py via a COPY into the image
  (single source of truth — blobs minted server-side verify against
  the same embedded pubkey on the buyer's machine).
- Source adapter Protocol (app/adapters/base.py) is the seam for
  Gumroad / Lemon Squeezy / Stripe in later PRs; Mint API speaks
  only SaleEvent / RefundEvent.
- (source, source_order_id) UNIQUE composite gives idempotent
  webhook retries without double-mint.
- JSONB type uses with_variant(JSON, 'sqlite') so the same models
  drive both Postgres prod and SQLite tests (no testcontainers dep).
- Bearer-token auth on /internal/*; the IP-loopback guard was
  removed after the docker bridge made it fight legitimate prod
  traffic (nginx defense + Bearer remain).
- Secrets resolved via *_FILE env vars pointing at
  /run/secrets/<name>, so passwords never appear in `docker inspect`.

21 unit tests (SQLite in-memory, StaticPool) plus a real-Postgres
docker-compose smoke test in server/scripts/smoke.sh that builds the
image, runs the alembic migration, mints a license, verifies the
signature against the host dev pubkey, and checks the DB row.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/tests/conftest.py

@@ -0,0 +1,108 @@
+"""Shared pytest fixtures.
+
+Tests run against in-memory SQLite — no docker, no Postgres install.
+The cross-dialect type variants in :mod:`app.models` keep the schema
+identical in behavior for everything PR 1 exercises (the JSONB
+column on ``gumroad_events`` isn't touched until PR 2).
+
+Auth: a fixed test token is wired into the settings cache before any
+app modules import, and the ``client`` fixture overrides the
+``require_localhost`` guard since Starlette's TestClient connects
+from a synthetic ``testclient`` peer.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+from pathlib import Path
+
+# Set required env BEFORE importing anything from app.* so pydantic
+# Settings (lru_cache'd) picks up these values on first access.
+os.environ["DATATOOLS_ADMIN_TOKEN"] = "test-admin-token"
+os.environ["DATABASE_URL"] = "sqlite+pysqlite:///:memory:"
+
+# Make the desktop license module importable as `datatools_license`.
+# In the Docker image this happens via `COPY src/license /app/datatools_license`;
+# during local tests we simulate it by aliasing src.license.
+_REPO_ROOT = Path(__file__).resolve().parents[2]
+sys.path.insert(0, str(_REPO_ROOT))
+import src.license as _dt_license_module
+sys.modules.setdefault("datatools_license", _dt_license_module)
+for _sub in ("crypto", "schema", "features", "_dev_keypair"):
+    sys.modules.setdefault(
+        f"datatools_license.{_sub}",
+        __import__(f"src.license.{_sub}", fromlist=[_sub]),
+    )
+
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy import create_engine, event
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.pool import StaticPool
+
+import app.db as app_db
+from app.db import Base
+from app.main import app
+
+
+@pytest.fixture(scope="session")
+def engine():
+    eng = create_engine(
+        "sqlite+pysqlite:///:memory:",
+        connect_args={"check_same_thread": False},
+        poolclass=StaticPool,
+        future=True,
+    )
+
+    # Enforce foreign keys on SQLite (off by default).
+    @event.listens_for(eng, "connect")
+    def _fk_on(dbapi_conn, _):
+        dbapi_conn.execute("PRAGMA foreign_keys=ON")
+
+    Base.metadata.create_all(eng)
+    yield eng
+    eng.dispose()
+
+
+@pytest.fixture(autouse=True)
+def _bind_app_engine(engine, monkeypatch):
+    """Point the app's session factory at the test engine and wipe rows
+    between tests so order-of-execution can't leak state."""
+    TestSession = sessionmaker(bind=engine, autoflush=False, autocommit=False, expire_on_commit=False)
+    monkeypatch.setattr(app_db, "engine", engine)
+    monkeypatch.setattr(app_db, "SessionLocal", TestSession)
+    yield
+    with engine.begin() as conn:
+        for tbl in reversed(Base.metadata.sorted_tables):
+            conn.execute(tbl.delete())
+
+
+@pytest.fixture
+def db_session(engine):
+    """Per-test session with rollback isolation."""
+    Session = sessionmaker(bind=engine, autoflush=False, autocommit=False, expire_on_commit=False)
+    sess = Session()
+    try:
+        yield sess
+    finally:
+        # Clean rows between tests rather than transaction-rolling (the
+        # mint code flushes mid-transaction and we want each test to
+        # see a clean licenses table).
+        sess.rollback()
+        for tbl in reversed(Base.metadata.sorted_tables):
+            sess.execute(tbl.delete())
+        sess.commit()
+        sess.close()
+
+
+@pytest.fixture
+def client():
+    """Plain TestClient. Bearer-token check is live."""
+    with TestClient(app) as c:
+        yield c
+
+
+@pytest.fixture
+def admin_headers() -> dict[str, str]:
+    return {"Authorization": "Bearer test-admin-token"}