Enforce sequential task orchestration

iso/builder/config/hooks/normal/9001-wallpaper.hook.chroot

@@ -44,23 +44,27 @@ else:
 img  = Image.new('RGB', (W, H), (0, 0, 0))
 draw = ImageDraw.Draw(img)
 
-# Measure logo block
+# Measure logo block line by line to avoid font ascender offset
 lines = LOGO.split('\n')
-bbox = draw.textbbox((0, 0), LOGO, font=font_logo)
-text_w = bbox[2] - bbox[0]
-text_h = bbox[3] - bbox[1]
+logo_lines = lines[:6]
+sub_line   = lines[6] if len(lines) > 6 else ''
 
-x = (W - text_w) // 2
-y = (H - text_h) // 2
+line_h = SIZE + 2
+block_h = len(logo_lines) * line_h + 8 + (SIZE if sub_line else 0)
 
-# Draw logo lines: first 6 in amber, last line (subtitle) dimmer
-logo_lines  = lines[:6]
-sub_line    = lines[6] if len(lines) > 6 else ''
+# Width: measure the widest logo line
+max_w = 0
+for line in logo_lines:
+    bb = draw.textbbox((0, 0), line, font=font_logo)
+    max_w = max(max_w, bb[2] - bb[0])
+
+x = (W - max_w) // 2
+y = (H - block_h) // 2
 
 cy = y
 for line in logo_lines:
     draw.text((x, cy), line, font=font_logo, fill=(0xf6, 0xc9, 0x0e))
-    cy += SIZE + 2
+    cy += line_h
 cy += 8
 if sub_line:
     draw.text((x, cy), sub_line, font=font_sub, fill=(0x80, 0x68, 0x18))