herdr: move config to prdlk/herdr external; document OSC 8 links

docs/chezmoi/index.mdx

@@ -55,7 +55,6 @@ The repo is a [chezmoi](https://chezmoi.io) source directory. It lives at `~/.lo
   - gh/
   - gh-dash/
   - ghostty/
-  - herdr/
   - herdr-nvim/
   - hunk/
   - hypr/
@@ -107,7 +106,7 @@ chezmoi encodes target names and attributes in source file names. These are the
 | `private_` | Target has group/world permissions cleared (`0600`/`0700`) | `dot_config/atuin/private_config.toml`, `dot_config/gh/private_config.yml`, `dot_config/hunk/private_state.json` |
 | `executable_` | Target gets the executable bit | 44 files: every script in `dot_local/bin/` (including `executable_tmux-niri-title`) and `dot_config/niri/scripts/` |
 | `exact_` | Directory is exact: entries in the target that are not in the source are deleted | `dot_config/niri/exact_config.d/` (numbered `10-…kdl` through `95-…kdl` fragments) |
-| `empty_` | File is kept even when empty | `dot_config/herdr/empty_dot_plugins.lock` |
+| `empty_` | File is kept even when empty | None currently |
 | `symlink_` | Target is a symlink; file content is the link destination | None currently |
 | `.tmpl` | Rendered with Go templates and chezmoi data | `dot_gitconfig.tmpl`, `dot_config/shell/aliases.sh.tmpl`, all scripts, the config and ignore files |
 | `run_once_` / `run_onchange_` + `before_` / `after_` | Script, with run frequency and phase | See [Apply scripts](/chezmoi/scripts) |