refactor(validations): split lib/validations.ts into a barrel'd folder (slice 1)

1141-line lib/validations.ts → lib/validations/<feature>.ts + primitives.ts +
an index.ts barrel. '@/lib/validations' now resolves to the barrel, so all 40
importers are untouched. Every one of the 143 exports is preserved verbatim
(verified by symbol-diff); schemas moved unchanged. tsc 0, 635 tests green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/validations/auth.ts

@@ -0,0 +1,30 @@
+import { z } from 'zod'
+import { emailField } from './primitives'
+
+export const signInSchema = z.object({
+  email: emailField(),
+  password: z.string().min(1, 'Password is required'),
+})
+
+export const signUpSchema = z.object({
+  email: emailField(),
+  password: z.string().min(8, 'Password must be at least 8 characters'),
+  fullName: z.string().min(1, 'Full name is required').max(100, 'Name is too long'),
+  action: z.enum(['create', 'join']),
+  spaceName: z.string().max(100).optional(),
+  spaceSlug: z.string().regex(/^[a-z0-9]+$/, 'Slug must be lowercase letters and numbers only').max(50).optional(),
+  city: z.string().max(100).optional(),
+  inviteCode: z.string().max(20).optional(),
+})
+
+export const createSpaceSchema = z.object({
+  spaceName: z.string().min(1, 'Space name is required').max(100, 'Name is too long'),
+  spaceSlug: z.string().min(1, 'Slug is required').max(50).regex(/^[a-z0-9]+$/, 'Slug must be lowercase letters and numbers only'),
+  spaceCity: z.string().max(100).optional(),
+  displayName: z.string().min(1, 'Display name is required').max(100),
+})
+
+export const joinSpaceSchema = z.object({
+  inviteCode: z.string().min(1, 'Invite code is required').max(20),
+  displayName: z.string().min(1, 'Display name is required').max(100),
+})