Say the terminal explicitly, only from a login session, and name the unannounced pull request (hq ADR 0272)

- commandEnvironment takes the terminal as a bool instead of reading an
  empty verb as one; every non-terminal line names its verb and is stripped
  of MESH_CLI_TERMINAL, and a test with the mark set in the serving
  environment fails when that strip is taken out.
- On the control-node the operator's account is the terminal only from a
  login session, as the node-engine reads it from the kernel's cgroup; the
  tool runner and the account's user units run as the operator too, and are
  ordinary calls. The request carries `session` (field-name tests on both
  sides).
- A pull request the forge never announced is named with its number in
  the condition's headline (hq issue 347), from the stalled line's
  `number`, which mesh-delivery sends.

cmd/mesh-controller/meshcli_test.go

@@ -25,7 +25,7 @@ var cliNodes = []inventory.Node{
 }
 
 func asked(account string, uid uint32, line ...string) link.CLIAsked {
-	return link.CLIAsked{Line: line, Account: account, UID: uid}
+	return link.CLIAsked{Line: line, Account: account, UID: uid, Session: "session-1.scope"}
 }
 
 // Who is the controller's terminal, and who is an ordinary call or refused (novox/hq ADR 0272 §4).
@@ -264,3 +264,42 @@ func TestTheCallsVerbNeverShowsAMeshCLILinesAnswer(t *testing.T) {
 		t.Fatalf("calls showed a mesh-cli line's answer: %s", said)
 	}
 }
+
+// **Only the terminal's line carries the terminal's mark** (review of ADR 0272): a mark the serving controller's
+// environment holds — leaked, or set by anything — is stripped from every other command line it runs, a verb's and
+// an ordinary mesh-cli line alike, so neither reads as the terminal.
+func TestTheTerminalsMarkIsStrippedFromEveryOtherLine(t *testing.T) {
+	t.Setenv(echoEnvironment, "1")
+	t.Setenv(cliTerminalVar, "1")
+	t.Setenv(servedVar, "1")
+	for _, env := range [][]string{commandEnvironment("someone", "status", false)} {
+		for _, kv := range env {
+			if strings.HasPrefix(kv, cliTerminalVar+"=") {
+				t.Fatalf("a verb's line carries the terminal's mark: %s", kv)
+			}
+		}
+	}
+	a := runForMeshCLI(context.Background(), "laptop", asked("operator", 1000, "status"), cliVerdict{why: "not the terminal"})
+	if got := string(a.Stdout); !strings.Contains(got, "terminal=false") || !strings.Contains(got, `verb="mesh-cli"`) {
+		t.Fatalf("an ordinary line with the mark in the serving environment ran as %s", got)
+	}
+	a = runForMeshCLI(context.Background(), "control", asked("operator", 1000, "status"), cliVerdict{terminal: true})
+	if got := string(a.Stdout); !strings.Contains(got, "terminal=true") {
+		t.Fatalf("the terminal's line ran as %s", got)
+	}
+}
+
+// **Only a login session is the terminal** (review of ADR 0272): the operator's account on the control-node, asking
+// from a service — the tool runner, a user unit — and not a login session, is an ordinary call.
+func TestOnlyALoginSessionIsTheTerminal(t *testing.T) {
+	control := []string{"control"}
+	v := judgeCLI("control", link.CLIAsked{Line: []string{"status"}, Account: "operator", UID: 1000}, cliNodes, control)
+	if v.terminal || v.refused != "" || !strings.Contains(v.why, "login session") {
+		t.Fatalf("a line from no login session reads %+v", v)
+	}
+	v = judgeCLI("control", link.CLIAsked{Line: []string{"status"}, Account: "operator", UID: 1000, Session: "session-3.scope"},
+		cliNodes, control)
+	if !v.terminal {
+		t.Fatalf("a line from a login session on the control-node reads %+v", v)
+	}
+}