feat(builder): documented launch options only, and no game-specific code

Launch options must be documented. A draft passed an option its server
doesn't have; servers ignore unknown options, so it booted and passed every
boot test while its setting did nothing. build now reads the pages research
based the variant on, in full, and the drafter rejects any launch option in
the startup command that none of them, nor the image's own scripts, mention.
Shell tools' options (mkdir -p, [ -n ...]) are skipped; the check is off
without sources.

The builder is game-agnostic:
- AUTHORING.md (the model's rules), the research prompt and the schema
  describe the rules without naming a game.
- The draft prompt no longer includes real templates from the repo. Its
  format example is one invented server (no real command, options, ports or
  app id), checked by TestExampleTemplateFollowsTheRules.
- Comments, help texts, BUILDER.md and test fixtures use invented names and
  values.
- TestBuilderIsGameAgnostic reads every game's name and id from games/ and
  fails if any appears in the builder's code, tests, rules, schemas or docs.

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

cmd/gbrgames/draft.go

@@ -13,7 +13,6 @@ import (
 	"path"
 	"path/filepath"
 	"regexp"
-	"sort"
 	"strings"
 	"time"
 
@@ -39,7 +38,7 @@ func runDraft(args []string) error {
 	fs := flag.NewFlagSet("draft", flag.ExitOnError)
 	gamesDir := fs.String("games", "games", "directory holding one folder per game")
 	schemaDir := fs.String("schemas", "schema", "directory holding the JSON Schemas")
-	gameName := fs.String("name", "", "the game's name, e.g. \"Valheim\"")
+	gameName := fs.String("name", "", "the game's name, as players know it")
 	id := fs.String("id", "", "folder/id for the new game (default: from -name)")
 	image := fs.String("image", "", "Docker image the server runs in")
 	steamApp := fs.String("steam-app", "", "SteamCMD app id, if the server is installed with SteamCMD")
@@ -82,6 +81,9 @@ type draftJob struct {
 	Report              *bootReport
 	Provider, Model     string
 	NoPull              bool
+	// Text of the pages research based the variant on; when set, every launch option in the startup
+	// command must appear in it (or in the image's scripts)
+	Docs string
 }
 
 // drafter holds one conversation with the model about one game, so later problems (a failed boot) can
@@ -137,7 +139,7 @@ func newDrafter(j draftJob) (*drafter, error) {
 	}
 	d.messages = []chatMessage{
 		{Role: "system", Content: draftSystemPrompt(string(rules))},
-		{Role: "user", Content: draftRequest(j.Name, id, j.Image, j.SteamApp, j.Notes, d.facts, j.Report, exampleTemplates(j.GamesDir, 2))},
+		{Role: "user", Content: draftRequest(j.Name, id, j.Image, j.SteamApp, j.Notes, d.facts, j.Report)},
 	}
 	return d, nil
 }
@@ -200,6 +202,7 @@ func (d *drafter) check(answer string) []string {
 			problems = append(problems, savesOutsideVolumes(g, d.job.Report)...)
 			problems = append(problems, splitSettings(g)...)
 			problems = append(problems, portSettings(g)...)
+			problems = append(problems, undocumentedOptions(g, d.job.Docs, d.facts)...)
 		}
 	}
 	return problems
@@ -337,7 +340,7 @@ func closestVar(name string, vars []string) string {
 var outsideNoise = []string{"/Steam/logs/", "/.steam/", "/steamcmd/", "/.cache/", "/tmp/", "/.local/share/umu"}
 
 // savesOutsideVolumes turns first boot's "written outside the volumes" into a hard check: anything the
-// game itself wrote there (Valheim's worlds and admin lists in ~/.config/unity3d/...) is lost every time the
+// game itself wrote there (worlds or player lists under the user's home folder) is lost every time the
 // node recreates the container. A template passes once its startup command or settings point the game at
 // /server or /data; a boot test then shows whether that really worked.
 func savesOutsideVolumes(game map[string]any, report *bootReport) []string {
@@ -403,7 +406,7 @@ func imageUnusable(r *bootReport) string {
 		*r.ExitCode, r.RanSeconds, r.User, denied[0])
 }
 
-func draftRequest(gameName, id, image, steamApp, notes string, facts *imageFacts, report *bootReport, examples string) string {
+func draftRequest(gameName, id, image, steamApp, notes string, facts *imageFacts, report *bootReport) string {
 	var b strings.Builder
 	fmt.Fprintf(&b, "Write the template for **%s**.\n- id: %s\n- defaultDockerImage: %s\n", gameName, id, image)
 	if steamApp != "" {
@@ -447,33 +450,62 @@ func draftRequest(gameName, id, image, steamApp, notes string, facts *imageFacts
 	} else {
 		b.WriteString("\n(No first-boot report: keep readyPattern out unless the facts show the ready line.)\n")
 	}
-	b.WriteString("\n## Working templates from this repo, for format and style (not content)\n")
-	b.WriteString(examples)
+	b.WriteString("\n## Format example\nAn invented server, to show the format and house style only. Its command, options, " +
+		"ports and app id belong to no real game: never copy them; take every value from the facts above.\n```yaml\n")
+	b.WriteString(exampleTemplate)
+	b.WriteString("```\n")
 	return b.String()
 }
 
-// exampleTemplates picks the shortest templates in the repo as examples: real, validated, and small
-// enough to leave the model room for the facts.
-func exampleTemplates(gamesDir string, n int) string {
-	entries, _ := os.ReadDir(gamesDir)
-	type ex struct {
-		id   string
-		body string
-	}
-	var all []ex
-	for _, e := range entries {
-		raw, err := os.ReadFile(filepath.Join(gamesDir, e.Name(), "game.yaml"))
-		if err == nil {
-			all = append(all, ex{e.Name(), string(raw)})
-		}
-	}
-	sort.Slice(all, func(i, j int) bool { return len(all[i].body) < len(all[j].body) })
-	var b strings.Builder
-	for i := 0; i < n && i < len(all); i++ {
-		fmt.Fprintf(&b, "\n### games/%s/game.yaml\n```yaml\n%s```\n", all[i].id, all[i].body)
-	}
-	return b.String()
-}
+// exampleTemplate shows the model the format only. It's invented on purpose: the builder must stay
+// game-agnostic, so the model never sees another game's template (whose options it would copy). Its
+// command, options, port and app id belong to no real server; validated in draft_test.go.
+const exampleTemplate = `id: example-server
+name: Example Server
+defaultDockerImage: cm2network/steamcmd
+defaultStartupCommand: args=(-name "${SERVER_NAME}" -world "${WORLD_NAME:-world}" -port 30000 -datadir /server/saves); [ -n "${JOIN_PASSWORD}" ] && args+=(-password "${JOIN_PASSWORD}"); ./example_server "${args[@]}"
+requiredMemoryMb: 4096
+requiredDiskMb: 8192
+defaultPorts:
+  - 30000/udp
+  - 30001/udp
+installMethod: STEAMCMD
+installConfig:
+  appId: "1000000"
+defaultConfig:
+  JoinPassword: ""
+  ServerName: GBRHosting - {SERVER_NAME}
+  WorldName: world
+configSchema:
+  type: object
+  properties:
+    JoinPassword:
+      title: Join Password
+      description: Password players enter to join. Leave empty for a public server.
+      type: string
+      default: ""
+      category: Security & Access
+      x-savedValue:
+        key: GAME_JOIN_PASSWORD
+        label: Game join password
+        secret: true
+    ServerName:
+      title: Server Name
+      description: The name shown in the server browser.
+      type: string
+      default: GBRHosting - {SERVER_NAME}
+      category: System & General
+      showOnDeploy: true
+    WorldName:
+      title: World Name
+      description: The world to load. A new name starts a new world.
+      type: string
+      default: world
+      category: World & Environment
+backupPaths:
+  - saves
+readyPattern: 'Server is ready for connections'
+`
 
 // writeDraft turns the model's JSON answer into games/<id>/game.yaml and test.yaml, using the importer's
 // writer so drafts look like every other template.