hscontrol/servertest: expand issue tests to 24 scenarios, surface 4 issues

Split TestIssues into 7 focused test functions to stay under cyclomatic
complexity limits while testing more aggressively.

Issues surfaced (4 failing tests):

1. initial_map_should_include_peer_online_status: Initial MapResponse
   has Online=nil for peers. Online status only arrives later via
   PeersChangedPatch.

2. disco_key_should_propagate_to_peers: DiscoPublicKey set by client
   is not visible to peers. Peers see zero disco key.

3. approved_route_without_announcement_is_visible: Server-side route
   approval without client-side announcement silently produces empty
   SubnetRoutes (intersection of empty announced + approved = empty).

4. nodestore_correct_after_rapid_reconnect: After 5 rapid reconnect
   cycles, NodeStore reports node as offline despite having an active
   poll session. The connect/disconnect grace period interleaving
   leaves IsOnline in an incorrect state.

Passing tests (20) verify:
- IP uniqueness across 10 nodes
- IP stability across reconnect
- New peers have addresses immediately
- Node rename propagates to peers
- Node delete removes from all peer lists
- Hostinfo changes (OS field) propagate
- NodeStore/DB consistency after route mutations
- Grace period timing (8-20s window)
- Ephemeral node deletion (not just offline)
- 10-node simultaneous connect convergence
- Rapid sequential node additions
- Reconnect produces complete map
- Cross-user visibility with default policy
- Same-user multiple nodes get distinct IDs
- Same-hostname nodes get unique GivenNames
- Policy change during connect still converges
- DERP region references are valid
- User profiles present for self and peers
- Self-update arrives after route approval
- Route advertisement stored as AnnouncedRoutes

hscontrol/servertest/ephemeral_test.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/juanfont/headscale/hscontrol/servertest"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"tailscale.com/types/netmap"
 )
 
@@ -52,25 +53,32 @@ func TestEphemeralNodes(t *testing.T) {
 
 		regular.WaitForPeers(t, 1, 10*time.Second)
 
+		// Verify ephemeral peer is present before disconnect.
+		_, found := regular.PeerByName("eph-cleanup-ephemeral")
+		require.True(t, found, "ephemeral peer should be visible before disconnect")
+
+		// Ensure the ephemeral node's long-poll session is fully
+		// established on the server before disconnecting. Without
+		// this, the Disconnect may cancel a PollNetMap that hasn't
+		// yet reached serveLongPoll, so no grace period or ephemeral
+		// GC would ever be scheduled.
+		ephemeral.WaitForPeers(t, 1, 10*time.Second)
+
 		// Disconnect the ephemeral node.
 		ephemeral.Disconnect(t)
 
-		// After the grace period (10s) + ephemeral timeout (3s) +
-		// some propagation time, the regular node should no longer
-		// see the ephemeral node. This tests the full cleanup path.
-		regular.WaitForCondition(t, "ephemeral peer gone or offline",
+		// After the grace period (10s) + ephemeral timeout (3s),
+		// the ephemeral node should be deleted from the server and
+		// disappear from the regular node's peer list entirely.
+		// Unlike non-ephemeral nodes which go offline but stay in
+		// the peer list, ephemeral nodes should be garbage collected.
+		regular.WaitForCondition(t, "ephemeral peer removed from peer list",
 			60*time.Second,
 			func(nm *netmap.NetworkMap) bool {
 				for _, p := range nm.Peers {
 					hi := p.Hostinfo()
 					if hi.Valid() && hi.Hostname() == "eph-cleanup-ephemeral" {
-						// Still present -- check if offline.
-						isOnline, known := p.Online().GetOk()
-						if known && !isOnline {
-							return true // offline is acceptable
-						}
-
-						return false // still online
+						return false // still present
 					}
 				}