Address PR review feedback: throw on unexpected end of input in Read-LuaValue

Author: MariusStorhaug

src/functions/private/Read-LuaValue.ps1

@@ -18,7 +18,7 @@
         Skip-LuaWhitespace
 
         if ($script:luaPos -ge $script:luaString.Length) {
-            return $null
+            throw 'Unexpected end of input'
         }
 
         $char = $script:luaString[$script:luaPos]

tests/Lua.Tests.ps1

@@ -499,6 +499,14 @@ B = { val = 2 }
         It 'Throws on unterminated table (missing closing brace)' {
             { ConvertFrom-Lua -InputObject '{ a = 1' } | Should -Throw '*Unterminated*'
         }
+
+        It 'Throws on whitespace-only input' {
+            { ConvertFrom-Lua -InputObject '   ' } | Should -Throw '*Unexpected end of input*'
+        }
+
+        It 'Throws on assignment with missing value' {
+            { ConvertFrom-Lua -InputObject 'A = ' } | Should -Throw '*Unexpected end of input*'
+        }
     }
 
     Context 'Pipeline input' {