types: restore Supabase row typing, fix parseInput inference (586→76 tsc errors)

The installed supabase-js (2.99, 5 generics) is incompatible with
@supabase/[email protected] (calls it with 3), collapsing the server client's
schema to `never` — the root cause of ~450 of the 586 hidden type errors
(next.config typescript.ignoreBuildErrors masks them all).

- lib/supabase/server.ts: annotate the factory as SupabaseClient<Database>
  and bridge the ssr/js impedance mismatch at the one documented boundary;
  type the setAll cookie params.
- lib/supabase/proxy.ts, proxy.ts: type the setAll cookie params.
- lib/auth-helpers.ts: parseInput now infers its result from the schema via
  z.infer (was a fragile ZodSchema<T> that widened outputs to {}).
- lib/validations.ts: annotate flexibleDateTime's output type.
- types/database.ts: add class_signup_tx / class_cancel_tx RPC signatures
  (called but absent; pending full regeneration).
- tsconfig.json: target ES2020 (door-log-logic uses BigInt literals).
- vitest.setup.ts: import beforeAll/afterAll instead of relying on globals.

No runtime behavior change; 639 tests still green. ignoreBuildErrors stays
on until the remaining errors reach zero.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

lib/auth-helpers.ts

@@ -1,6 +1,6 @@
 import type { SupabaseClient } from '@supabase/supabase-js'
 import type { Tables } from '@/types/database'
-import type { ZodSchema } from 'zod'
+import type { ZodTypeAny, TypeOf } from 'zod'
 import { ACTIVE_STATUSES, hasRole, isPrivilegeEligible, type Role } from '@/lib/permissions'
 
 /**
@@ -97,7 +97,10 @@ export async function requireMemberWithRole(
  * so callers can `if (!v.ok) return { error: v.error }` and have `v.data`
  * narrowed to T.
  */
-export function parseInput<T>(schema: ZodSchema<T>, input: unknown): Result<T> {
+export function parseInput<S extends ZodTypeAny>(
+  schema: S,
+  input: unknown,
+): Result<TypeOf<S>> {
   const parsed = schema.safeParse(input)
   if (!parsed.success) {
     return { ok: false, error: parsed.error.errors[0]?.message ?? 'Invalid input' }