docs: add BSD-3-Clause headers to generated files and update CI docs

asm/loong64_assemble.go

@@ -0,0 +1,23 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: BSD-3-Clause
+
+package asm
+
+import (
+	"fmt"
+
+	"sourcedock.dev/petrbalvin/gasm-devkit/ast"
+)
+
+// assembleLOONG64 is a stub.  The loong64 (LoongArch) instruction encoder is
+// not yet implemented — the instruction tables, register files and operand-count
+// metadata are in place (package arch), and the lexer, parser, formatter and
+// linter already handle loong64 source files.
+func assembleLOONG64(t *ast.Text) ([]byte, map[string]int, []Reloc, error) {
+	return nil, nil, nil, fmt.Errorf("loong64 instruction encoding is not yet implemented")
+}
+
+// AssembleFileLOONG64 is a stub, returning the same error as assembleLOONG64.
+func AssembleFileLOONG64(f *ast.File) (*Image, error) {
+	return nil, fmt.Errorf("loong64 instruction encoding is not yet implemented")
+}