ci: boot-test changed games before publishing

Only games whose folder changed are boot-tested (against the previous
main commit, or against main on branches; manual runs pick games). Each
one is deployed by the node-agent's real deploy code on a dedicated
game-test runner, in a network that can reach the internet but not the
LAN. Publishing to the panel runs only if they all booted.

- boottest-payload builds the DEPLOY_SERVER message the panel would send
- readyPattern/failPatterns in game.yaml; readyExample in test.yaml is
  checked against the pattern during validation
- secrets in test.yaml come from CI; a game missing one is skipped
- Minecraft gets a ready pattern; Dragonwilds needs DRAGONWILDS_OWNER_ID
- RUNNER.md + scripts/runner: runner, isolated network, systemd unit

Also fixes newline values ("\n" separators/footers) that yaml.v3 wrote
as "" on import, which would have broken ARK and Dragonwilds config
files once synced, and adds a round-trip test for the importer.

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

cmd/gbrgames/validate.go

@@ -94,6 +94,17 @@ func validateGame(dir, folder string, gameSchema, testSchema *jsonschema.Schema)
 	}
 	scanPrivateIPs(raw, "game.yaml", add)
 
+	// Go's regexp is a subset of Java's, which the node-agent uses; anything that compiles here works there
+	patterns, _ := g["failPatterns"].([]any)
+	if p, ok := g["readyPattern"].(string); ok {
+		patterns = append(patterns, p)
+	}
+	for _, p := range patterns {
+		if _, err := regexp.Compile(fmt.Sprint(p)); err != nil {
+			add("pattern %q does not compile: %v", p, err)
+		}
+	}
+
 	defaults, _ := g["defaultConfig"].(map[string]any)
 	props := schemaProperties(g)
 	known := map[string]bool{}
@@ -165,6 +176,14 @@ func validateGame(dir, folder string, gameSchema, testSchema *jsonschema.Schema)
 			add("test.yaml secrets.%s is not a key of this game", key)
 		}
 	}
+	if example, ok := t["readyExample"].(string); ok {
+		pattern, _ := g["readyPattern"].(string)
+		if re, err := regexp.Compile(pattern); pattern == "" || err != nil {
+			add("test.yaml has a readyExample but the game has no valid readyPattern")
+		} else if !re.MatchString(example) {
+			add("readyPattern %q does not match test.yaml readyExample %q", pattern, example)
+		}
+	}
 	return problems
 }