fix(deps): revert supabase CLI bump, breaks edge function test seeding

The 2.70.0 -> 2.115.0 bump appears to change `supabase db reset` seed
behavior, causing the Edge Function Tests CI job to fail with
"No festival edition found". Reverting to keep this PR's CI green;
the CLI security fix needs its own PR once the seeding regression is
diagnosed against a reproducible Supabase environment.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014JqTa7k1smvXm4AbVzBhqt

Author: claude

package.json

@@ -126,7 +126,7 @@
     "oxlint": "^1.79.0",
     "postcss": "^8.5.26",
     "prettier": "3.6.2",
-    "supabase": "2.115.0",
+    "supabase": "2.70.0",
     "tailwindcss": "^3.4.19",
     "tsx": "^4.23.12",
     "typescript": "^5.9.3",