test: add comprehensive unit test suite for FileTypeSupport

shared/src/main/kotlin/io/askimo/core/chat/util/FileTypeSupport.kt

@@ -43,18 +43,6 @@ object FileTypeSupport {
         "nix", "dhall",
     )
 
-    /**
-     * Config files without extensions (treated as code files).
-     */
-    val CONFIG_EXTENSIONS = setOf(
-        "dockerfile",
-        "makefile",
-        "gemfile",
-        "rakefile",
-        "procfile",
-        "vagrantfile",
-    )
-
     /**
      * Document file extensions (for content extraction).
      */
@@ -76,6 +64,23 @@ object FileTypeSupport {
         "bmp",
     )
 
+    /**
+     * Extensionless configuration filenames stored in lowercase.
+     * These files have no extension but are recognised by their full filename.
+     */
+    val CONFIG_EXTENSIONS = setOf(
+        "dockerfile",
+        "makefile",
+        "jenkinsfile",
+        "procfile",
+        "vagrantfile",
+        "rakefile",
+        "gemfile",
+        "podfile",
+        "brewfile",
+        "guardfile",
+    )
+
     /**
      * All text-extractable file extensions.
      * These files have their content extracted and included in the prompt.
@@ -119,4 +124,13 @@ object FileTypeSupport {
      * @return The extension without the dot, or empty string if no extension
      */
     fun getExtension(fileName: String): String = fileName.substringAfterLast('.', "")
+
+    /**
+     * Check if a filename is a known extensionless configuration file.
+     * Comparison is case-insensitive.
+     *
+     * @param fileName The file name (without path)
+     * @return true if the filename is in CONFIG_EXTENSIONS
+     */
+    fun isConfigFile(fileName: String): Boolean = fileName.lowercase() in CONFIG_EXTENSIONS
 }