chore: strip remaining pre-fork version references

Second pass — removes chat-switchboard version numbers from config
field docs, section headers, file headers, and test comments. These
were pre-fork version tags that don't apply to switchboard-core.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/pages/pages.go

@@ -629,7 +629,7 @@ type WorkflowLandingPageData struct {
 	PersonaName string
 	PersonaIcon string
 	StageCount     int
-	FirstStageMode string // custom | form_only | form_chat (v0.29.3)
+	FirstStageMode string // custom | form_only | form_chat
 	ResumeURL      string // non-empty if visitor has an active session
 }
 
@@ -649,7 +649,7 @@ func (e *Engine) RenderWorkflow() gin.HandlerFunc {
 		// Load session display name
 		sessionName := "Visitor"
 
-		// Load workflow stage info for form rendering (v0.29.3)
+		// Load workflow stage info for form rendering
 		var stageMode, stageName, formTplJSON, surfacePkgID, brandingJSON string
 		var totalStages, currentStage int
 		stageMode = "custom" // default