skills: install only prdlk/skills, prune other sources; prompt to replace non-checkout external targets

docs/ai/README.md

@@ -4,13 +4,13 @@ The shared agent skill library and the shell entry points for coding agents.
 
 The repo manages the agent skill library only. Claude Code (`~/.claude`) and omp (`~/.omp`) configs are not in this repo. omp, opencode, and crush are global mise tools (`packages.shared.mise`, installed by [15-tools](../chezmoi/scripts.md#15-tools)) and are updated by topgrade's `mise upgrade`; no other agent CLI is installed by chezmoi.
 
-- [Skills](skills.md): Agent skills declared in `.chezmoidata/skills.yaml` and installed into `~/.agents/skills` and `~/.claude/skills` by an apply script.
+- [Skills](skills.md): Every agent skill in [prdlk/skills](https://github.com/prdlk/skills), installed into `~/.agents/skills` and `~/.claude/skills` by an apply script.
 
 ## Pages
 
 | Page | Source in repo | Target in `$HOME` | Covers |
 | --- | --- | --- | --- |
-| [Skills](skills.md) | `.chezmoidata/skills.yaml`, `.chezmoiscripts/run_onchange_after_25-skills.sh.tmpl` | `~/.agents/skills/`, `~/.claude/skills/` | Skill list and sources; installed by the Skills CLI, not vendored |
+| [Skills](skills.md) | `.chezmoidata/skills.yaml`, `.chezmoiscripts/run_onchange_after_25-skills.sh.tmpl` | `~/.agents/skills/`, `~/.claude/skills/` | The prdlk/skills source and skill list; installed by the Skills CLI, not vendored |
 
 ## Shell entry points