Probe every access review connector on status check

Bad API keys and expired OAuth tokens showed Connected because
probes ran only for OAuth2 and many providers had no ProbeURL.
Add a registry ProbeConnection dispatcher with static, dynamic,
and custom probes so all 41 providers are checked on demand.

Signed-off-by: Bryan Frimin <bryan@probo.com>

pkg/connector/provider/probe_test.go

@@ -0,0 +1,92 @@
+// Copyright (c) 2026 Probo Inc <hello@probo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package provider
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.probo.inc/probo/pkg/coredata"
+)
+
+func TestBuiltinRegistry_ProbeCoverage(t *testing.T) {
+	t.Parallel()
+
+	r := NewBuiltinRegistry()
+
+	for _, reg := range r.All() {
+		hasProbe := reg.Probe != nil || reg.ProbeURL != "" || reg.BuildProbeURL != nil
+		assert.True(t, hasProbe, "provider %s has no connection probe configured", reg.Provider)
+	}
+}
+
+func TestBuildDatadogProbeURL(t *testing.T) {
+	t.Parallel()
+
+	conn := &coredata.Connector{Provider: coredata.ConnectorProviderDatadog}
+	require.NoError(t, conn.SetSettings(&coredata.DatadogConnectorSettings{
+		Domain: "us3.datadoghq.com",
+		Region: "US3",
+	}))
+
+	probeURL, err := buildDatadogProbeURL(conn)
+	require.NoError(t, err)
+	assert.Equal(
+		t,
+		"https://api.us3.datadoghq.com/api/v2/users?page%5Bnumber%5D=0&page%5Bsize%5D=1",
+		probeURL,
+	)
+}
+
+func TestBuildZendeskProbeURL(t *testing.T) {
+	t.Parallel()
+
+	conn := &coredata.Connector{Provider: coredata.ConnectorProviderZendesk}
+	require.NoError(t, conn.SetSettings(&coredata.ZendeskConnectorSettings{
+		Subdomain: "acme",
+	}))
+
+	probeURL, err := buildZendeskProbeURL(conn)
+	require.NoError(t, err)
+	assert.Contains(t, probeURL, "https://acme.zendesk.com/api/v2/users.json")
+}
+
+func TestBuildOktaProbeURL(t *testing.T) {
+	t.Parallel()
+
+	conn := &coredata.Connector{Provider: coredata.ConnectorProviderOkta}
+	require.NoError(t, conn.SetSettings(&coredata.OktaConnectorSettings{
+		Domain: "acme.okta.com",
+	}))
+
+	probeURL, err := buildOktaProbeURL(conn)
+	require.NoError(t, err)
+	assert.Equal(t, "https://acme.okta.com/api/v1/users?limit=1", probeURL)
+}
+
+func TestBuildPostHogProbeURL(t *testing.T) {
+	t.Parallel()
+
+	conn := &coredata.Connector{Provider: coredata.ConnectorProviderPostHog}
+	require.NoError(t, conn.SetSettings(&coredata.PostHogConnectorSettings{
+		BaseURL: "https://us.posthog.com",
+	}))
+
+	probeURL, err := buildPostHogProbeURL(conn)
+	require.NoError(t, err)
+	assert.Equal(t, "https://us.posthog.com/api/organizations/@current/", probeURL)
+}