[management] Carry the ownership tests through the stack merge

The merge took this branch's side of the bootstrap test file wholesale, so
the ownership tests and their helper from the branch below were missing here
and read as deletions against it. Restore them, and drop this branch's copy
of the address-first test, which the ownership change now owns.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Sa3DsBDP3VciAi4PPG17L6

management/internals/modules/agentnetwork/settings_bootstrap_test.go

@@ -108,6 +108,21 @@ func (f *bootstrapFixture) seedEmbeddedCluster(t *testing.T, clusterAddr string)
 	f.seedProxy(t, "proxy-"+clusterAddr, "", clusterAddr, ptrTo(true))
 }
 
+// requireForeignClusterRefusal asserts the refusal a pin onto another
+// account's host gets, and that it left no row behind.
+func (f *bootstrapFixture) requireForeignClusterRefusal(t *testing.T, err error, accountID string) {
+	t.Helper()
+	require.Error(t, err, "another account's host must be refused")
+	var sErr *status.Error
+	require.ErrorAs(t, err, &sErr)
+	assert.Equal(t, status.InvalidArgument, sErr.Type(), "rejection must be a validation error")
+	assert.Contains(t, err.Error(), "not available to this account",
+		"the error must say the host is not the account's to use")
+
+	_, err = f.store.GetAgentNetworkSettings(context.Background(), store.LockingStrengthNone, accountID)
+	assert.Error(t, err, "no row may be left behind by a rejected bootstrap")
+}
+
 // TestCreateSettingsRequiresPermission pins the gate: bootstrap assigns the
 // account's immutable endpoint, a settings write requiring the settings
 // Create permission — and a denial leaves no row behind.
@@ -271,20 +286,6 @@ func TestCreateProviderHasNoSettingsSideEffects(t *testing.T) {
 	assert.Error(t, err, "provider create must not conjure a settings row")
 }
 
-// TestCreateSettingsAllowsUnknownCluster pins the one opening left: a cluster
-// management holds no proxy row for cannot be judged, so the pin is allowed —
-// the same order the dedicated path documents (claim the address, connect the
-// proxy after).
-func TestCreateSettingsAllowsUnknownCluster(t *testing.T) {
-	ctx := context.Background()
-	f := newBootstrapFixture(t)
-	f.expectPermission("account1", "user1", modules.AgentNetworkSettings, operations.Create, true)
-
-	created, err := f.createSettings(ctx, "account1", "user1", "future.example.com", "")
-	require.NoError(t, err, "a cluster no proxy has ever declared must stay pinnable")
-	assert.Equal(t, "future.example.com", created.ProxyAddress)
-}
-
 // TestCreateSettingsRejectsOfflineCluster is the guard against deciding on
 // heartbeat freshness. A centralised cluster is refused while its proxies are
 // live; the same cluster must stay refused once they stop heartbeating, which
@@ -387,3 +388,99 @@ func TestCreateSettingsMatchesClusterCasing(t *testing.T) {
 		assert.Contains(t, err.Error(), "embedded proxy")
 	})
 }
+
+// TestCreateSettingsRejectsForeignCluster pins tenant consistency on the pin:
+// an account may not pin its gateway onto a host another account's proxy
+// declares. That proxy only ever receives its own account's mappings, so the
+// pin could never be served, and the endpoint it assigns is immutable.
+// Ownership is decided on the proxy rows, not on heartbeat freshness — a
+// cluster whose proxies are merely offline is still somebody's — and on the
+// normalised host, since proxies declare their address as the operator
+// spelled it.
+func TestCreateSettingsRejectsForeignCluster(t *testing.T) {
+	ctx := context.Background()
+
+	cases := map[string]struct {
+		spelling string
+		lastSeen time.Time
+	}{
+		"live":            {"byop.account2.example.com", time.Now().UTC()},
+		"offline":         {"byop.account2.example.com", time.Now().UTC().Add(-time.Hour)},
+		"spelled in caps": {"BYOP.Account2.Example.com", time.Now().UTC()},
+	}
+	for name, tc := range cases {
+		t.Run("labeled "+name, func(t *testing.T) {
+			f := newBootstrapFixture(t)
+			f.seedProxyAt(t, "proxy1", "account2", tc.spelling, ptrTo(true), tc.lastSeen)
+			f.expectPermission("account1", "user1", modules.AgentNetworkSettings, operations.Create, true)
+
+			_, err := f.createSettings(ctx, "account1", "user1", "byop.account2.example.com", "")
+			f.requireForeignClusterRefusal(t, err, "account1")
+		})
+		t.Run("self-addressed "+name, func(t *testing.T) {
+			f := newBootstrapFixture(t)
+			f.seedProxyAt(t, "proxy1", "account2", tc.spelling, ptrTo(true), tc.lastSeen)
+			f.expectPermission("account1", "user1", modules.AgentNetworkSettings, operations.Create, true)
+
+			_, err := f.createSettings(ctx, "account1", "user1", "", "byop.account2.example.com")
+			f.requireForeignClusterRefusal(t, err, "account1")
+		})
+	}
+}
+
+// TestCreateSettingsSharedClusterStaysPinnable pins the constraint the
+// ownership check must respect: a shared (NetBird-operated) cluster is not
+// anybody's, so any number of accounts pin their gateways to it — including
+// an account that also runs a proxy of its own elsewhere.
+func TestCreateSettingsSharedClusterStaysPinnable(t *testing.T) {
+	ctx := context.Background()
+	f := newBootstrapFixture(t)
+	f.seedProxy(t, "shared", "", "eu.proxy.netbird.io", ptrTo(true))
+	f.seedProxy(t, "own", "account1", "byop.account1.example.com", ptrTo(true))
+
+	for _, account := range []string{"account1", "account2"} {
+		f.expectPermission(account, "user", modules.AgentNetworkSettings, operations.Create, true)
+		created, err := f.createSettings(ctx, account, "user", "eu.proxy.netbird.io", "")
+		require.NoError(t, err, "a shared cluster must stay pinnable by %s", account)
+		assert.Equal(t, "eu.proxy.netbird.io", created.ProxyAddress)
+	}
+}
+
+// TestCreateSettingsOwnClusterIsPinnable is the BYOP order in both directions:
+// the account's own proxy is not a competing claim, whether the pin is labeled
+// beneath its cluster or self-addressed onto the very host it declares.
+func TestCreateSettingsOwnClusterIsPinnable(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("labeled", func(t *testing.T) {
+		f := newBootstrapFixture(t)
+		f.seedProxy(t, "own", "account1", "byop.account1.example.com", ptrTo(true))
+		f.expectPermission("account1", "user1", modules.AgentNetworkSettings, operations.Create, true)
+
+		created, err := f.createSettings(ctx, "account1", "user1", "byop.account1.example.com", "")
+		require.NoError(t, err, "the account's own cluster must be pinnable")
+		assert.True(t, strings.HasSuffix(created.Domain, ".byop.account1.example.com"))
+	})
+	t.Run("self-addressed", func(t *testing.T) {
+		f := newBootstrapFixture(t)
+		f.seedProxy(t, "own", "account1", "gw.account1.example.com", ptrTo(true))
+		f.expectPermission("account1", "user1", modules.AgentNetworkSettings, operations.Create, true)
+
+		created, err := f.createSettings(ctx, "account1", "user1", "", "gw.account1.example.com")
+		require.NoError(t, err, "the host the account's own proxy declares must be pinnable")
+		assert.Equal(t, "gw.account1.example.com", created.ProxyAddress)
+	})
+}
+
+// TestCreateSettingsUnknownHostIsPinnable pins the address-first order: a host
+// no proxy has ever declared is nobody's, so the pin goes through and the
+// proxy is deployed after.
+func TestCreateSettingsUnknownHostIsPinnable(t *testing.T) {
+	ctx := context.Background()
+	f := newBootstrapFixture(t)
+	f.expectPermission("account1", "user1", modules.AgentNetworkSettings, operations.Create, true)
+
+	created, err := f.createSettings(ctx, "account1", "user1", "future.example.com", "")
+	require.NoError(t, err, "a host no proxy has declared must stay pinnable")
+	assert.Equal(t, "future.example.com", created.ProxyAddress)
+}