feat(api): M4.2 — REST surface + pgx Postgres store + OpenAPI 3.1

Full M4.2 deliverable: 16 endpoints (tenants CRUD + lifecycle, catalog, entitlements, API keys with argon2 hashing, audit append + filter), Store interface with pgx-backed Postgres + in-memory parallel implementations exercised by the same eachStore harness, openapi.yaml at 3.1 with kin-openapi contract test. M4.3 adds auth.

Refs: M4.2

internal/server/tenants_test.go

@@ -0,0 +1,115 @@
+package server_test
+
+import (
+	"net/http"
+	"testing"
+
+	"gitea.meghsakha.com/platform/tenant-registry/internal/store"
+)
+
+func TestHealthz(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		resp, _ := h.do("GET", "/healthz", nil)
+		if resp.StatusCode != 200 {
+			t.Fatalf("status = %d", resp.StatusCode)
+		}
+	})
+}
+
+func TestCreateTenant(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		resp, body := h.do("POST", "/v1/tenants", map[string]any{
+			"slug": "beta-co", "name": "Beta Co.", "plan": "starter",
+		})
+		if resp.StatusCode != http.StatusCreated {
+			t.Fatalf("status = %d, body=%s", resp.StatusCode, body)
+		}
+		t1 := decode[store.Tenant](t, body)
+		if t1.Slug != "beta-co" || t1.Status != "trial" || t1.Plan != "starter" {
+			t.Errorf("unexpected: %+v", t1)
+		}
+	})
+}
+
+func TestCreateTenant_invalidSlug(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		resp, _ := h.do("POST", "/v1/tenants", map[string]any{
+			"slug": "X", "name": "Bad",
+		})
+		if resp.StatusCode != http.StatusBadRequest {
+			t.Fatalf("status = %d", resp.StatusCode)
+		}
+	})
+}
+
+func TestCreateTenant_duplicateSlugConflict(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		// 'acme' is pre-seeded
+		resp, _ := h.do("POST", "/v1/tenants", map[string]any{
+			"slug": "acme", "name": "Dup",
+		})
+		if resp.StatusCode != http.StatusConflict {
+			t.Fatalf("status = %d", resp.StatusCode)
+		}
+	})
+}
+
+func TestGetTenantBySlug(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		resp, body := h.do("GET", "/v1/tenants/by-slug/acme", nil)
+		if resp.StatusCode != 200 {
+			t.Fatalf("status = %d", resp.StatusCode)
+		}
+		got := decode[store.Tenant](t, body)
+		if got.Slug != "acme" {
+			t.Errorf("slug = %q", got.Slug)
+		}
+	})
+}
+
+func TestGetTenantBySlug_notFound(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		resp, _ := h.do("GET", "/v1/tenants/by-slug/nope-nope", nil)
+		if resp.StatusCode != http.StatusNotFound {
+			t.Fatalf("status = %d", resp.StatusCode)
+		}
+	})
+}
+
+func TestActivateTenant(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		_, body := h.do("POST", "/v1/tenants", map[string]any{
+			"slug": "trial-co", "name": "Trial Co.",
+		})
+		created := decode[store.Tenant](t, body)
+		if created.Status != "trial" {
+			t.Fatalf("precondition: %q", created.Status)
+		}
+
+		resp, body := h.do("POST", "/v1/tenants/"+created.ID+"/activate", map[string]any{
+			"plan": "professional", "erp_customer_id": "ERP-001",
+		})
+		if resp.StatusCode != 200 {
+			t.Fatalf("status = %d, body=%s", resp.StatusCode, body)
+		}
+		got := decode[store.Tenant](t, body)
+		if got.Status != "active" || got.Plan != "professional" || got.ErpCustomerID != "ERP-001" {
+			t.Errorf("unexpected: %+v", got)
+		}
+	})
+}
+
+func TestCancelTenant(t *testing.T) {
+	eachStore(t, func(t *testing.T, h *testHarness) {
+		resp, body := h.do("POST", "/v1/tenants/"+h.tenant.ID+"/cancel", map[string]any{
+			"reason": "test", "at_period_end": true,
+		})
+		if resp.StatusCode != 200 {
+			t.Fatalf("status = %d, body=%s", resp.StatusCode, body)
+		}
+		got := decode[store.Tenant](t, body)
+		if got.Status != "frozen" {
+			t.Errorf("status = %q", got.Status)
+		}
+	})
+}