Split omarchy-plugin into siblings and consolidate bar config into omarchy-bar

omarchy-plugin mixed plugin lifecycle, clone/edit, and bar-layout mutation.
The bar layout was mutated by two separate engines (an embedded Python
mutate_bar here and jq in omarchy-config-shell-bar), each with its own
manifest walker.

- omarchy-plugin is now a ~220-line router; clone and edit move to
  omarchy-plugin-clone and omarchy-plugin-edit, matching the existing
  plugin-{source,add,update,remove,available,validate,scan} sibling pattern
- omarchy-config-shell-bar is replaced by omarchy-bar, the single bar engine
  (show/layout/list/options/use/reset/add/move/remove/set/replace/position/
  transparent/settings) with one jq pipeline; the Python mutate_bar and its
  python3 dependency are gone
- omarchy-plugin-catalog is the shared manifest scanner used by omarchy-bar
  (widget/option enumeration, add validation) and omarchy-plugin-clone
  (source enumeration), replacing three find|jq re-implementations
- service install/remove and refresh-shell call omarchy-bar; docs and tests
  updated to the new command surface

shell/plugins/bar/README.md

@@ -14,9 +14,9 @@ the shell for its whole session.
 
 ## Customizing
 
-The bar config lives under the `bar:` key of [`~/.config/omarchy/shell.json`](../../README.md#shelljson-shape). Out of the box the shell uses [`config/omarchy/shell.json`](../../../config/omarchy/shell.json). Once you customize anything via the inline bar config panel, `omarchy plugin bar ...`, or by editing shell.json directly, your file is canonical — there is no deep-merge.
+The bar config lives under the `bar:` key of [`~/.config/omarchy/shell.json`](../../README.md#shelljson-shape). Out of the box the shell uses [`config/omarchy/shell.json`](../../../config/omarchy/shell.json). Once you customize anything via the inline bar config panel, `omarchy bar ...`, or by editing shell.json directly, your file is canonical — there is no deep-merge.
 
-Open quick position and transparency controls with `omarchy launch bar settings` / `omarchy plugin bar settings` (or run `omarchy-launch-bar-settings`). You can also hover the centered clock module to reveal the inline bar config button. For scriptable widget changes, use `omarchy plugin bar list`, `omarchy plugin bar add`, `omarchy plugin bar move`, `omarchy plugin bar remove`, and `omarchy plugin bar set`. Double-left-click empty center-bar space to toggle bar transparency.
+Open quick position and transparency controls with `omarchy bar settings` (or run `omarchy-launch-bar-settings`). You can also hover the centered clock module to reveal the inline bar config button. For scriptable widget changes, use `omarchy bar list`, `omarchy bar add`, `omarchy bar move`, `omarchy bar remove`, and `omarchy bar set`. Double-left-click empty center-bar space to toggle bar transparency.
 
 Example `shell.json` (bar subtree only shown):
 
@@ -181,4 +181,4 @@ Third-party widgets ship as separate plugins under
 declaring `kinds: ["bar-widget"]` and a `barWidget` entry point. See
 [../../README.md](../../README.md) for the manifest schema. Enable,
 rescan, and place third-party plugins with `omarchy plugin enable`,
-`omarchy plugin rescan`, and `omarchy plugin bar add`.
+`omarchy plugin rescan`, and `omarchy bar add`.

shell/plugins/panels/tailscale/README.md

@@ -35,4 +35,4 @@ Renders the Tailscale mark natively as a theme-colored 3×3 dot grid, matching t
 
 ## Add to the bar
 
-This widget ships as first-party plugin `omarchy.tailscale`. Add it with `omarchy plugin bar add omarchy.tailscale`, or add an entry such as `{ "id": "omarchy.tailscale" }` to one of the `bar.layout` sections in `~/.config/omarchy/shell.json`; the shell reloads `shell.json` automatically.
+This widget ships as first-party plugin `omarchy.tailscale`. Add it with `omarchy bar add omarchy.tailscale`, or add an entry such as `{ "id": "omarchy.tailscale" }` to one of the `bar.layout` sections in `~/.config/omarchy/shell.json`; the shell reloads `shell.json` automatically.