PR #106: getUserIdFromRequest in supabase.ts still uses || "" pattern and creates a new client per call — dead code, should be removed

[bmersereau]

Problem

During review of PR #106, the batch reviewer identified that getUserIdFromRequest in backend/src/lib/supabase.ts was not updated as part of the env-guard fix. The function:

• Still uses the old || "" pattern for env vars
• Creates a fresh createClient on every call (no singleton)
• Has zero callers in the codebase — it is dead code

Since it is exported, leaving it in place risks it being wired to a route in the future with broken behavior.

Fix

Remove getUserIdFromRequest from supabase.ts entirely. Auth is handled by requireAuth middleware (auth.ts) which already uses the singleton pattern.

Affected

• Branch: fix/97-backend-supabase-env-guard
• PR: fix: throw on missing env vars in backend createServerSupabase() #106

[bmersereau]

Fixed in PR #106. getUserIdFromRequest has been removed from backend/src/lib/supabase.ts — it had no callers and was the only remaining function in that file using the old || "" env var pattern. Auth is handled exclusively by the requireAuth middleware in auth.ts. Closes when PR #106 merges.