feat(validation): add typed rule package #2

Summary

• Add typed, immutable rule builders with ordered failures and rule selection.
• Cover text, number, decimal, collection, nested, conditional, async, and result APIs.
• Establish package metadata, CLI, CI, contributor files, README, and source mirrors.

Validation

• pudu check $(rg --files src test -g '*.pudu')
• pudu fmt --check src test
• pudu lint src test
• pudu test test — 10 suites, 59 assertions
• Compiled CLI --version and --help smoke checks

Closes #1