feat: add prebuilt workspaces telemetry (#18084)

Adds telemetry for a _global_ account of prebuilt workspaces created,
failed to build, and claimed.

Partitioning this data by template/preset tuple is not currently in
scope.

---------

Signed-off-by: Danny Kopping <dannykopping@gmail.com>

coderd/telemetry/telemetry_test.go

@@ -370,6 +370,113 @@ func TestTelemetryItem(t *testing.T) {
 	require.Equal(t, item.Value, "new_value")
 }
 
+func TestPrebuiltWorkspacesTelemetry(t *testing.T) {
+	t.Parallel()
+	ctx := testutil.Context(t, testutil.WaitMedium)
+	db, _ := dbtestutil.NewDB(t)
+
+	cases := []struct {
+		name                    string
+		experimentEnabled       bool
+		storeFn                 func(store database.Store) database.Store
+		expectedSnapshotEntries int
+		expectedCreated         int
+		expectedFailed          int
+		expectedClaimed         int
+	}{
+		{
+			name:              "experiment enabled",
+			experimentEnabled: true,
+			storeFn: func(store database.Store) database.Store {
+				return &mockDB{Store: store}
+			},
+			expectedSnapshotEntries: 3,
+			expectedCreated:         5,
+			expectedFailed:          2,
+			expectedClaimed:         3,
+		},
+		{
+			name:              "experiment enabled, prebuilds not used",
+			experimentEnabled: true,
+			storeFn: func(store database.Store) database.Store {
+				return &emptyMockDB{Store: store}
+			},
+		},
+		{
+			name:              "experiment disabled",
+			experimentEnabled: false,
+			storeFn: func(store database.Store) database.Store {
+				return &mockDB{Store: store}
+			},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			deployment, snapshot := collectSnapshot(ctx, t, db, func(opts telemetry.Options) telemetry.Options {
+				opts.Database = tc.storeFn(db)
+				if tc.experimentEnabled {
+					opts.Experiments = codersdk.Experiments{
+						codersdk.ExperimentWorkspacePrebuilds,
+					}
+				}
+				return opts
+			})
+
+			require.NotNil(t, deployment)
+			require.NotNil(t, snapshot)
+
+			require.Len(t, snapshot.PrebuiltWorkspaces, tc.expectedSnapshotEntries)
+
+			eventCounts := make(map[telemetry.PrebuiltWorkspaceEventType]int)
+			for _, event := range snapshot.PrebuiltWorkspaces {
+				eventCounts[event.EventType] = event.Count
+				require.NotEqual(t, uuid.Nil, event.ID)
+				require.False(t, event.CreatedAt.IsZero())
+			}
+
+			require.Equal(t, tc.expectedCreated, eventCounts[telemetry.PrebuiltWorkspaceEventTypeCreated])
+			require.Equal(t, tc.expectedFailed, eventCounts[telemetry.PrebuiltWorkspaceEventTypeFailed])
+			require.Equal(t, tc.expectedClaimed, eventCounts[telemetry.PrebuiltWorkspaceEventTypeClaimed])
+		})
+	}
+}
+
+type mockDB struct {
+	database.Store
+}
+
+func (*mockDB) GetPrebuildMetrics(context.Context) ([]database.GetPrebuildMetricsRow, error) {
+	return []database.GetPrebuildMetricsRow{
+		{
+			TemplateName:     "template1",
+			PresetName:       "preset1",
+			OrganizationName: "org1",
+			CreatedCount:     3,
+			FailedCount:      1,
+			ClaimedCount:     2,
+		},
+		{
+			TemplateName:     "template2",
+			PresetName:       "preset2",
+			OrganizationName: "org1",
+			CreatedCount:     2,
+			FailedCount:      1,
+			ClaimedCount:     1,
+		},
+	}, nil
+}
+
+type emptyMockDB struct {
+	database.Store
+}
+
+func (*emptyMockDB) GetPrebuildMetrics(context.Context) ([]database.GetPrebuildMetricsRow, error) {
+	return []database.GetPrebuildMetricsRow{}, nil
+}
+
 func TestShouldReportTelemetryDisabled(t *testing.T) {
 	t.Parallel()
 	// Description                            | telemetryEnabled (db) | telemetryEnabled (is) | Report Telemetry Disabled |