add Star Maze demo

res/ATTRACT/STAR.MAZE

@@ -6,3 +6,4 @@
 STAR.MAZE=C
 STAR.MAZE2=A
 STAR.MAZE=A
+STAR.MAZE=0

src/demo/star.maze.a

@@ -0,0 +1,59 @@
+;license:MIT
+;(c) 2024 by qkumba
+
+!cpu 6502
+!to "build/DEMO/STAR.MAZE#060300",plain
+*=$300
+
+         !source "src/constants.a"   ; no code in these
+         !source "src/macros.a"
+
+         +READ_RAM2_WRITE_RAM2
+         jsr   EnableAccelerator
+         +LOAD_FILE_KEEP_DIR star_maze, star_maze_dir_e-star_maze_dir_b
+         +READ_ROM_NO_WRITE
+
+         lda   #$60
+         sta   $21FD
+         jsr   $2000      ; decompress
+         sta   $7A07
+         sty   $7A08      ; reset vector
+
+         lda   #<callback
+         sta   $7B3A
+         lda   #>callback
+         sta   $7B3B
+
+         lda   #$4C
+         sta   $7BD3
+         sta   $9849
+         ldx   #0
+         stx   $7BD4
+         stx   $984A
+         inx
+         stx   $7BD5
+         stx   $984B
+
+         +DISABLE_ACCEL
+         jmp   $79D3
+
+callback
+         dec   counter
+         beq   +
+         jmp   $87AB
++        jmp   $100
+
+counter  !byte 5
+
+star_maze
+         !byte star_maze_e-star_maze_b
+star_maze_b
+star_maze_dir_b
+         !text "X"
+star_maze_dir_e
+         !text "/STAR.MAZE"
+star_maze_e
+
+!if * > $3F0 {
+  !error "code is too large, ends at ", *
+}