fix(routes): add explicit redirects for /merchants and /admin without trailing slash

The CMS /{slug} catch-all at root level intercepts these paths before
FastAPI can redirect to the prefixed routers, causing a 404.

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

main.py

@@ -332,6 +332,24 @@ logger.info("=" * 80)
 logger.info("ROUTE REGISTRATION (AUTO-DISCOVERY)")
 logger.info("=" * 80)
 
+# =============================================================================
+# EXPLICIT REDIRECTS for paths that clash with the CMS /{slug} catch-all
+# =============================================================================
+# The CMS catch-all /{slug} at root level intercepts /merchants, /admin, etc.
+# (without trailing slash) before FastAPI can redirect to the prefixed routers.
+# These explicit routes ensure clean URLs work.
+
+
+@app.get("/merchants", include_in_schema=False)
+async def merchants_redirect():
+    return RedirectResponse(url="/merchants/", status_code=301)
+
+
+@app.get("/admin", include_in_schema=False)
+async def admin_redirect():
+    return RedirectResponse(url="/admin/", status_code=301)
+
+
 # =============================================================================
 # PLATFORM PAGES (Marketing pages - homepage, pricing, signup, etc.)
 # =============================================================================