Support Augment via native rules integration

Summary Add support for Augment / Auggie to rtk init using Augment's native rules directories.

Motivation RTK already supports multiple AI coding agents through hooks, plugins, or rules-based integrations. Augment now has public documentation for:

rules ( .augment/rules/ , ~/.augment/rules/ ) hooks plugins / marketplaces commands and skills This makes Augment a reasonable new target for RTK integration.

Proposed first step Add a rules-based integration instead of a transparent rewrite integration:

rtk init --agent augment → write ./.augment/rules/rtk.md rtk init -g --agent augment → write ~/.augment/rules/rtk.md Why rules-first According to Augment's current hook documentation, PreToolUse can intercept tool execution, but it does not yet support modifying tool input. That means RTK cannot currently implement the same transparent command rewrite flow used for Claude Code / Cursor.

A rules-first integration would still provide immediate value while staying aligned with Augment's documented capabilities.

Scope Proposed scope for an initial PR:

add augment to supported rtk init agent targets install RTK guidance into Augment's native rules directories document Augment as rules-based support avoid claiming transparent rewrite support for now Future follow-up If Augment later supports tool input mutation / command rewrite in hooks, RTK could be upgraded to a transparent hook-based integration in a later PR.

Question Would maintainers accept a first PR scoped to rules-only Augment support?