feat: outbound webhooks — signed event delivery + delivery log

Every audited action now emits a "resource.action" event (bare actions
get resource-qualified; already-qualified actions like service.clone
pass through). Webhooks subscribe per-user with exact names, resource.*
wildcards, or *.

- schema: outbound_webhooks + webhook_deliveries (sqlc + goose)
- dispatcher: 4 workers, 512-queue, 3 attempts with backoff, 10s timeout;
  deliveries record status/http-code/body(4KiB)/duration
- signing: X-Containr-Signature sha256=<hmac> over raw body;
  X-Containr-Event + X-Containr-Delivery headers; custom headers per hook
- api: CRUD + /deliveries + /test (ping) under authed group
- fix: SetAuditDB never called — LogAudit was a silent no-op at every
  call site; now wired at boot
- coverage: service create/delete audited (previously uninstrumented)
- cli: containr webhooks list|create|update|delete|deliveries|test
- mcp: 6 tools, delete requires confirm
- frontend: /settings/webhooks page — list/create/expand-deliveries/
  test/disable/delete, secret-shown-once banner; nav + account menu
- openapi + regenerated types; CLI.md + docs snapshot; roadmap ticks

app/backend/internal/api/webhooks_test.go

@@ -0,0 +1,33 @@
+package api
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestWebhookEventMatches(t *testing.T) {
+	subs := func(list ...string) json.RawMessage {
+		raw, _ := json.Marshal(list)
+		return raw
+	}
+	cases := []struct {
+		events json.RawMessage
+		event  string
+		want   bool
+	}{
+		{subs("service.*"), "service.deploy", true},
+		{subs("service.*"), "database.create", false},
+		{subs("*"), "service.deploy", true},
+		{subs("deployment.fail", "service.*"), "deployment.fail", true},
+		{subs("deployment.fail"), "deployment.success", false},
+		{subs(" ping "), "ping", true},
+		{subs(), "service.deploy", false},
+		{json.RawMessage(`"not-a-list"`), "service.deploy", false},
+		{json.RawMessage(`invalid`), "service.deploy", false},
+	}
+	for i, tc := range cases {
+		if got := webhookEventMatches(tc.events, tc.event); got != tc.want {
+			t.Errorf("case %d: matches(%s, %q) = %v, want %v", i, tc.events, tc.event, got, tc.want)
+		}
+	}
+}