fix(boot-test): run every boot test with exactly what a new server gets

CI's boot test gave every blank password-like setting a throwaway value. A
real deploy only fills x-generate fields, so a template whose server won't
start without one passed CI and failed for the first owner who deployed it.

boottest-payload now fills only x-generate fields, for CI and the builder
alike. The old behaviour is kept as -fill-blank-passwords, used only by
the builder's second boot to tell whether an empty setting is why a draft
fails. Messages and AUTHORING.md no longer say boot tests fill passwords;
a server that needs a join password gets x-generate.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/gbrgames/build.go

@@ -236,7 +236,7 @@ func bootCheck(gamesDir, id, agentImage string, wantOutside bool) (problems, ver
 	if out, err := runCmd("docker", "pull", "-q", agentImage); err != nil {
 		return nil, nil, fmt.Errorf("docker pull %s: %v: %s", agentImage, err, out)
 	}
-	output, passed, problems, err := agentBoot(gamesDir, id, agentImage, true)
+	output, passed, problems, err := agentBoot(gamesDir, id, agentImage, false)
 	if err != nil || problems != nil {
 		return problems, nil, err
 	}
@@ -246,7 +246,7 @@ func bootCheck(gamesDir, id, agentImage string, wantOutside bool) (problems, ver
 		if blank := blankRequiredLooking(gamesDir, id); len(blank) > 0 {
 			fmt.Printf("[build] it failed with the defaults; booting again with %s filled to see whether empty settings are the cause\n",
 				strings.Join(blank, ", "))
-			if _, filledPassed, _, err := agentBoot(gamesDir, id, agentImage, false); err == nil && filledPassed {
+			if _, filledPassed, _, err := agentBoot(gamesDir, id, agentImage, true); err == nil && filledPassed {
 				return []string{emptySettingsProblem(blank, bootVerdict(output))}, nil, nil
 			}
 		}
@@ -271,10 +271,10 @@ func bootCheck(gamesDir, id, agentImage string, wantOutside bool) (problems, ver
 	return nil, verified, nil
 }
 
-// agentBoot runs one boot test with the node-agent's BootTest: with the settings a new server gets
-// (asDeployed), or with blank password-like settings filled with throwaway values as CI's boot test does.
-// problems is set when the template can't be boot-tested at all.
-func agentBoot(gamesDir, id, agentImage string, asDeployed bool) (output string, passed bool, problems []string, err error) {
+// agentBoot runs one boot test with the node-agent's BootTest, with the settings a new server gets, like
+// CI. fillBlank also fills blank password-like settings, only to find out whether they are why a draft
+// fails. problems is set when the template can't be boot-tested at all.
+func agentBoot(gamesDir, id, agentImage string, fillBlank bool) (output string, passed bool, problems []string, err error) {
 	self, err := os.Executable()
 	if err != nil {
 		return "", false, nil, err
@@ -284,8 +284,8 @@ func agentBoot(gamesDir, id, agentImage string, asDeployed bool) (output string,
 	runCmd("docker", "rm", "-f", "boottest-"+id)
 	runCmd("docker", "volume", "rm", "-f", "boottest-"+id+"-data")
 	args := []string{"boottest-payload", "-games", gamesDir, id}
-	if asDeployed {
-		args = []string{"boottest-payload", "-as-deployed", "-games", gamesDir, id}
+	if fillBlank {
+		args = []string{"boottest-payload", "-fill-blank-passwords", "-games", gamesDir, id}
 	}
 	payloadCmd := exec.Command(self, args...)
 	var stderr bytes.Buffer
@@ -296,7 +296,7 @@ func agentBoot(gamesDir, id, agentImage string, asDeployed bool) (output string,
 		if errors.As(err, &exitErr) && exitErr.ExitCode() == exitMissingSecret {
 			// The builder has no CI secrets: that's the template's problem to fix, not a reason to stop
 			return "", false, []string{"the boot test can't run: " + strings.TrimSpace(stderr.String()) + ". Remove 'secrets' from " +
-				"test.yaml; boot tests fill password settings with a throwaway value"}, nil
+				"test.yaml; boot tests run with exactly what a new server gets"}, nil
 		}
 		return "", false, nil, fmt.Errorf("boottest-payload: %v: %s", err, strings.TrimSpace(stderr.String()))
 	}
@@ -317,8 +317,8 @@ func agentBoot(gamesDir, id, agentImage string, asDeployed bool) (output string,
 	return out.String(), true, nil, nil
 }
 
-// blankRequiredLooking lists the settings a new server gets empty that CI's boot test would fill with a
-// throwaway value: password-like keys with an empty default and no x-generate.
+// blankRequiredLooking lists the settings a new server gets empty that look like a server might need a
+// value: password-like keys with an empty default and no x-generate.
 func blankRequiredLooking(gamesDir, id string) []string {
 	g, err := loadMap(filepath.Join(gamesDir, id, "game.yaml"))
 	if err != nil {