Simplify omarchy-bar into a bar-settings and bar-plugin split

The omarchy-bar command had grown three overlapping ways to inspect the
bar (show/layout/list/options, plus selected/active/available/widgets
aliases) and mixed layout mutation in with bar-level settings. Untangle
it into two focused commands:

- omarchy-bar keeps only the bar-level settings that write shell.json:
  use, reset, position, transparent, and settings. reset now delegates
  to `use omarchy.bar` rather than duplicating the del(.bar.id) write.
- omarchy-bar-plugin owns all layout mutation: add, move, remove, set,
  and replace, with the placement flags and jq resolve/anchor helpers.
  `omarchy bar plugin ...` routes here via the dispatcher.

Drop the inspection commands entirely: the layout is visible on the bar,
the config is shell.json, and widget/option ids come from
`omarchy plugin list`. Nothing consumed the show output programmatically
except tests. This also removes omarchy-bar-position, whose jq write was
a duplicate of `omarchy bar position`.

Strip environment-invariant guards (require_command, require_omarchy_path)
that defended against jq or OMARCHY_PATH being absent — neither happens on
a real system. Keep the user-input validation (--section/--index) and the
atomic shell.json write.

Update callers (service install/remove, refresh-shell, plugin-clone,
plugin enable), keybindings, the menu, tests, and docs to the new split.

shell/plugins/bar/README.md

@@ -10,13 +10,13 @@ the shell for its whole session.
 - `widgets/` holds simple first-party bar widgets with sibling manifests.
 - Feature plugins such as `../panels/audio/`, `../panels/network/`, `../panels/power/`, and `../model-usage/` provide richer popup bar plugins.
 - The bar receives its config from the host shell as a `barConfig` property; the host loads it from `~/.config/omarchy/shell.json` (or `config/omarchy/shell.json` when the user has no file).
-- `omarchy-bar-position` updates only the user shell.json file.
+- `omarchy bar position` updates only the user shell.json file.
 
 ## 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 bar ...`, or by editing shell.json directly, your file is canonical — there is no deep-merge.
 
-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.
+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 plugin add`, `omarchy bar plugin move`, `omarchy bar plugin remove`, and `omarchy bar plugin set` (widget ids come from `omarchy plugin list`). 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 bar add`.
+`omarchy plugin rescan`, and `omarchy bar plugin 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 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 plugin 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.