feat(campaign): make the label source a cell dimension

A 2x2 of policy against labelling needs the runner to express both factors.
It could only express the policy, so half the factorial had to go through
--extra, where the manifest would not record what was actually run.

Rejected at parse rather than on dispatch: a sweep that finds the bad value
on run 1 of 40 has already spent a cell's worth of device time.

Claude-Session: https://claude.ai/code/session_01A5KmftdEJ49A9z5mF5ESrX

cmd/internal-tools/campaign/main.go

@@ -23,6 +23,7 @@ type config struct {
 	platform        string
 	arm             string
 	generator       string
+	labelSource     string
 	maxSteps        int
 	duration        time.Duration
 	seeds           []int64
@@ -58,6 +59,7 @@ func parseArguments(arguments []string, stderr io.Writer) (config, error) {
 	flagSet.StringVar(&configuration.platform, "platform", "android", "target platform: android, ios, web")
 	flagSet.StringVar(&configuration.arm, "arm", "", "experiment cell label recorded on every run (required)")
 	flagSet.StringVar(&configuration.generator, "generator", "seeded", "action generator: seeded or llm")
+	flagSet.StringVar(&configuration.labelSource, "label-source", "visible-text", "how candidates are named to the llm generator: visible-text (what a user reads) or resource-id (the identifier the app assigned). The seeded generator picks by index and ignores this")
 	flagSet.IntVar(&configuration.maxSteps, "max-steps", 0, "per-run step budget (required, must be positive)")
 	flagSet.DurationVar(&configuration.duration, "duration", 5*time.Minute, "per-run wall-clock ceiling")
 	flagSet.StringVar(&seedSpecification, "seeds", "", "seeds to run: ranges and lists, e.g. 1-10,20,30-32 (required)")
@@ -91,6 +93,13 @@ func parseArguments(arguments []string, stderr io.Writer) (config, error) {
 	default:
 		return config{}, fmt.Errorf("unsupported generator: %q (seeded, llm)", configuration.generator)
 	}
+	// Rejected before the first run, because a sweep that discovers the bad
+	// value on run 1 of 40 has already spent the device time of a whole cell.
+	switch configuration.labelSource {
+	case "visible-text", "resource-id":
+	default:
+		return config{}, fmt.Errorf("unsupported label source: %q (visible-text, resource-id)", configuration.labelSource)
+	}
 	if configuration.maxSteps <= 0 {
 		// Steps to first violation is right-censored at the budget, so a
 		// campaign without one has nothing to censor its clean runs at.
@@ -170,6 +179,7 @@ func runArguments(configuration config, seed, device string) []string {
 		"--platform", configuration.platform,
 		"--arm", configuration.arm,
 		"--generator", configuration.generator,
+		"--label-source", configuration.labelSource,
 		"--max-steps", strconv.Itoa(configuration.maxSteps),
 		"--duration", configuration.duration.String(),
 		"--seed", seed,