feat: add Team billing tier

Widens the tier enum from free/pro to free/pro/team and every
"free" | "pro" cast that assumed exactly two tiers (~30 call sites:
every AI route's withAiQuota/checkAndIncrementTierLimit call, admin
user/invite management, upload quota checks, OpenAPI schemas). Team
sits above Pro with genuinely unlimited recipes/public-recipes (the
-1 sentinel, which Pro doesn't actually use — Pro uses large finite
numbers instead) and a higher AI-call/storage cap. Seeded via
db:seed, editable afterward from Admin > Tiers.

role (user/moderator/admin — permissions) and tier (free/pro/team —
billing limits) stay separate concepts, as they already were; this
does not touch role-based permissions.

Requires migration 0043 to run against a live DB — not applied in
this sandbox (no Docker here); run `pnpm db:migrate` then `pnpm db:seed`.

v0.44.0

apps/web/lib/tiers.ts

@@ -35,12 +35,12 @@ export class TierLimitError extends Error {
  */
 export async function checkAndIncrementTierLimit(
   userId: string,
-  fallbackTier: "free" | "pro",
+  fallbackTier: "free" | "pro" | "team",
   key: "recipe" | "aiCall" | "storage",
   amount = 1
 ): Promise<void> {
   const [dbUser] = await db.select({ tier: users.tier }).from(users).where(eq(users.id, userId));
-  const userTier = (dbUser?.tier as "free" | "pro" | undefined) ?? fallbackTier;
+  const userTier = (dbUser?.tier as "free" | "pro" | "team" | undefined) ?? fallbackTier;
 
   const [tierDef] = await db
     .select()