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

test/shell.d/runtime-smoke-test.sh

@@ -220,7 +220,7 @@ for panel_id in omarchy.audio omarchy.bluetooth omarchy.monitor omarchy.network
 done
 pass "direct panel IPC opens and closes default panels"
 
-HOME="$test_home" OMARCHY_PATH="$test_root" PATH="$ROOT/bin:$PATH" "$ROOT/bin/omarchy-config-shell-bar" remove omarchy.audio
+HOME="$test_home" OMARCHY_PATH="$test_root" PATH="$ROOT/bin:$PATH" "$ROOT/bin/omarchy-bar" remove omarchy.audio
 
 for _ in {1..80}; do
   shell_config=$(shell_ipc shell listShellConfig 2>/dev/null || true)
@@ -237,7 +237,7 @@ done
 
 jq -e 'all(.bar.layout.right[]; (.id // .) != "omarchy.audio")' <<<"$shell_config" >/dev/null || {
   printf 'Shell config after reload:\n%s\n' "$shell_config" | jq . >&2
-  fail_with_log "config shell bar remove reloads shell config"
+  fail_with_log "bar remove reloads shell config"
 }
 
 jq -e 'all(.[]; .id != "omarchy.audio")' <<<"$geometry" >/dev/null || {
@@ -246,4 +246,4 @@ jq -e 'all(.[]; .id != "omarchy.audio")' <<<"$geometry" >/dev/null || {
   fail_with_log "runtime bar layout updates after shell config reload"
 }
 
-pass "config shell bar remove reloads shell config and updates bar layout"
+pass "bar remove reloads shell config and updates bar layout"