fix(arch): extend TPL-009 block name check to merchant templates

The block name validation (scripts → extra_scripts, etc.) only checked
admin and store templates, missing merchant. Added is_merchant flag.
This would have caught the {% block scripts %} bug in merchant/team.html.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/validate/validate_architecture.py

@@ -848,6 +848,7 @@ class ArchitectureValidator:
         is_admin = "/admin/" in file_path_str or "\\admin\\" in file_path_str
         is_store = "/store/" in file_path_str or "\\store\\" in file_path_str
         is_shop = "/shop/" in file_path_str or "\\shop\\" in file_path_str
+        is_merchant = "/merchant/" in file_path_str or "\\merchant\\" in file_path_str
 
         if is_base_or_partial:
             print("⏭️  Skipping base/partial template")
@@ -881,8 +882,8 @@ class ArchitectureValidator:
             # TPL-008: Check for call table_header() pattern (should be table_header_custom)
             self._check_table_header_call_pattern(file_path, content, lines)
 
-            # TPL-009: Check for invalid block names (admin and store use same blocks)
-            if is_admin or is_store:
+            # TPL-009: Check for invalid block names (admin, store, and merchant use same blocks)
+            if is_admin or is_store or is_merchant:
                 self._check_valid_block_names(file_path, content, lines)
 
         if is_base_or_partial: