refactor: rename Wizamart to Orion across entire codebase

Replace all ~1,086 occurrences of Wizamart/wizamart/WIZAMART/WizaMart
with Orion/orion/ORION across 184 files. This includes database
identifiers, email addresses, domain references, R2 bucket names,
DNS prefixes, encryption salt, Celery app name, config defaults,
Docker configs, CI configs, documentation, seed data, and templates.

Renames homepage-wizamart.html template to homepage-orion.html.
Fixes duplicate file_pattern key in api.yaml architecture rule.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/core/celery_config.py

@@ -1,6 +1,6 @@
 # app/core/celery_config.py
 """
-Celery configuration for Wizamart background task processing.
+Celery configuration for Orion background task processing.
 
 This module configures Celery with Redis as the broker and result backend.
 It includes:
@@ -66,7 +66,7 @@ def get_all_task_modules() -> list[str]:
 
 # Create Celery application
 celery_app = Celery(
-    "wizamart",
+    "orion",
     broker=REDIS_URL,
     backend=REDIS_URL,
     include=get_all_task_modules(),