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/delivery_conditions.go

@@ -33,12 +33,14 @@ var deliveryOwnerWithin = 10 * time.Second
 
 // stalledLine is one delivery past its bound, as mesh-delivery's `stalled` says it.
 type stalledLine struct {
-	ID    string `json:"id"`
-	State string `json:"state"`
-	For   string `json:"for"`
-	Bound string `json:"bound"`
-	H2    string `json:"h2"`
-	Says  string `json:"says"`
+	ID string `json:"id"`
+	// Number is the pull request's, for a line of a head the forge never announced (novox/hq issue 347).
+	Number int    `json:"number,omitempty"`
+	State  string `json:"state"`
+	For    string `json:"for"`
+	Bound  string `json:"bound"`
+	H2     string `json:"h2"`
+	Says   string `json:"says"`
 }
 
 // operatorsOnly is whether the table leaves H2 nothing to do for the line: the state is the operator's.