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/alembic/versions/0001_initial.py

@@ -0,0 +1,80 @@
+"""Initial schema — licenses + gumroad_events.
+
+Revision ID: 0001_initial
+Revises:
+Create Date: 2026-05-14
+"""
+
+from __future__ import annotations
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+from sqlalchemy.dialects import postgresql
+
+revision: str = "0001_initial"
+down_revision: Union[str, None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "licenses",
+        sa.Column("license_key", sa.String(), primary_key=True),
+        sa.Column("name", sa.String(), nullable=False),
+        sa.Column("email", sa.String(), nullable=False),
+        sa.Column("tier", sa.String(), nullable=False),
+        sa.Column("issued_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("blob", sa.String(), nullable=False),
+        sa.Column("source", sa.String(), nullable=False),
+        sa.Column("source_order_id", sa.String(), nullable=True),
+        sa.Column("promotion", sa.String(), nullable=True),
+        sa.Column("amount_paid", sa.Numeric(10, 2), nullable=True),
+        sa.Column("currency", sa.String(length=3), server_default=sa.text("'USD'"), nullable=True),
+        sa.Column("revoked_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("notes", sa.String(), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.UniqueConstraint("source", "source_order_id", name="uq_licenses_source_order"),
+    )
+    op.create_index(
+        "ix_licenses_email_lower",
+        "licenses",
+        [sa.text("lower(email)")],
+    )
+    op.create_index(
+        "ix_licenses_expires_active",
+        "licenses",
+        ["expires_at"],
+        postgresql_where=sa.text("revoked_at IS NULL"),
+    )
+
+    op.create_table(
+        "gumroad_events",
+        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
+        sa.Column("received_at", sa.DateTime(timezone=True), server_default=sa.text("now()"), nullable=False),
+        sa.Column("event_type", sa.String(), nullable=False),
+        sa.Column("order_id", sa.String(), nullable=True),
+        sa.Column("raw_payload", postgresql.JSONB(), nullable=False),
+        sa.Column("processed", sa.Boolean(), server_default=sa.text("false"), nullable=False),
+        sa.Column("error", sa.String(), nullable=True),
+    )
+    op.create_index("ix_gumroad_events_order_id", "gumroad_events", ["order_id"])
+    op.create_index(
+        "ix_gumroad_events_unprocessed",
+        "gumroad_events",
+        ["received_at"],
+        postgresql_where=sa.text("processed = false"),
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_gumroad_events_unprocessed", table_name="gumroad_events")
+    op.drop_index("ix_gumroad_events_order_id", table_name="gumroad_events")
+    op.drop_table("gumroad_events")
+    op.drop_index("ix_licenses_expires_active", table_name="licenses")
+    op.drop_index("ix_licenses_email_lower", table_name="licenses")
+    op.drop_table("licenses")