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/tasks.ts

@@ -0,0 +1,15 @@
+import { z } from 'zod'
+import { flexibleDateTime } from './primitives'
+
+export const createTaskSchema = z.object({
+  title: z.string().min(1, 'Title is required').max(200, 'Title is too long'),
+  description: z.string().max(2000, 'Description is too long').optional(),
+  type: z.enum(['task', 'chore']).default('task'),
+  area: z.string().max(100).optional(),
+  recurrence: z.enum(['none', 'daily', 'weekly', 'biweekly', 'monthly']).default('none'),
+  due_date: flexibleDateTime().optional(),
+})
+
+export const taskIdSchema = z.string().uuid('Invalid task ID')
+
+export type CreateTaskInput = z.infer<typeof createTaskSchema>