Fix string literals that trigger ESM shim plugin rewriting

Strings containing `import '`, `import "`, or `import(` in the JS
bundle cause esmShimPlugin/Vite to misinterpret them as ES module
imports and corrupt the output. Split or rephrase all 7 occurrences
across 4 shared-source files. Added comments explaining the
constraint so future changes don't reintroduce the pattern.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: respencer-ncl

language/shared/src/main/scala/com/ossuminc/riddl/language/AST.scala

@@ -985,14 +985,24 @@ object AST:
     /** Check if this is a selective import (imports a specific definition) */
     def isSelective: Boolean = kindOpt.isDefined && selector.isDefined
 
+    // NOTE: The RIDDL keyword "import" must NOT appear adjacent to a
+    // quote character (' or ") in any string literal that reaches the
+    // JS bundle.  ESM shim plugins (e.g. esmShimPlugin / Vite) scan
+    // the compiled JS for patterns like  import '…  or  import "…
+    // and rewrite them, corrupting the output.  We split the keyword
+    // with string concatenation so the pattern never appears in the
+    // bundle as a single token.  Do NOT "simplify" these into a
+    // single interpolated string.
+    private val imp = "im" + "port"
+
     def format: String =
       if isSelective then
         val kindStr = kindOpt.getOrElse("")
         val selectorStr = selector.map(_.value).getOrElse("")
         val aliasStr = alias.map(a => s" as ${a.value}").getOrElse("")
-        s"""import $kindStr $selectorStr from "${path.s}"$aliasStr"""
+        s"""$imp $kindStr $selectorStr from "${path.s}"$aliasStr"""
       else
-        s"""import "${path.s}""""
+        imp + " \"" + path.s + "\""
     override def toString: String = format
   end BASTImport
 

language/shared/src/main/scala/com/ossuminc/riddl/language/bast/BASTLoader.scala

@@ -58,9 +58,11 @@ object BASTLoader {
           }
           loaded += 1
         case Left(error) =>
+          // NOTE: avoid "import '" in string literals — ESM shim
+          // plugins misinterpret it as an ES module import statement.
           msgs += Messages.Message(
             bi.loc,
-            s"Failed to load BAST import '${bi.path.s}': $error",
+            s"Failed to load BAST file '${bi.path.s}': $error",
             Messages.Error
           )
           failed += 1

language/shared/src/main/scala/com/ossuminc/riddl/language/parsing/TopLevelParser.scala

@@ -82,11 +82,13 @@ object TopLevelParser:
   private def loadBASTImports(root: Root, baseURL: URL)(using pc: PlatformContext): (Root, Messages) = {
     if BASTLoader.hasUnloadedImports(root) then
       val result = BASTLoader.loadImports(root, baseURL)
+      // NOTE: avoid "import(" in string literals — ESM shim plugins
+      // misinterpret it as a dynamic ES module import() call.
       if result.failedCount > 0 then
-        pc.log.warn(s"Failed to load ${result.failedCount} BAST import(s)")
+        pc.log.warn(s"Failed to load ${result.failedCount} BAST file(s)")
       end if
       if result.loadedCount > 0 then
-        pc.log.info(s"Loaded ${result.loadedCount} BAST import(s)")
+        pc.log.info(s"Loaded ${result.loadedCount} BAST file(s)")
       end if
       (root, result.messages)
     else

passes/shared/src/main/scala/com/ossuminc/riddl/passes/validate/ValidationPass.scala

@@ -496,9 +496,11 @@ case class ValidationPass(
     check(i.origin.nonEmpty, "Include has no source provided", Messages.Error, i.loc)
   }
 
+  // NOTE: avoid "import '" in string literals — ESM shim plugins
+  // misinterpret it as an ES module import statement.
   private def validateBASTImport(bi: BASTImport, parents: Parents): Unit = {
-    check(bi.path.s.nonEmpty, "BAST import has no path specified", Messages.Error, bi.loc)
-    check(bi.path.s.endsWith(".bast"), s"BAST import path '${bi.path.s}' should end with .bast", Messages.Warning, bi.loc)
+    check(bi.path.s.nonEmpty, "BAST load has no path specified", Messages.Error, bi.loc)
+    check(bi.path.s.endsWith(".bast"), s"BAST load path '${bi.path.s}' should end with .bast", Messages.Warning, bi.loc)
   }
 
   private def validateEntity(