Honor keepLoaded for services during plugin hot-reload (#9485)

* Honor keepLoaded for services during plugin hot-reload

Plugin reload destroyed every service, including omarchy.lock, which drops the ext-session-lock client while Hyprland still holds the lock and surfaces the crashed-lockscreen fallback.

* Prove keepLoaded service survival with a fixture service

A fresh lock service also reports an empty lastEventAt, so comparing it
across the rescan passed whether or not the instance survived. A fixture
keepLoaded service whose in-memory marker is set before the rescan and
read back after can only pass when the same instance is still mounted.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Drop kept services whose plugin no longer declares a service

The _syncServices cleanup only asked whether the plugin was still
installed and enabled, so a kept service whose plugin dropped its
service kind or entry point kept running as a zombie until shell
restart. Apply the same eligibility checks used at creation, and hand
kept instances the refreshed manifest after a rescan.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Cover omarchy.media in keepLoaded expectations; note kept services reload on restart

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: David Heinemeier Hansson <david@hey.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
(cherry picked from commit d3d23fddde)

docs/omarchy-shell.md

@@ -34,9 +34,7 @@ first call.
 
 Only one full bar option is active at a time. The built-in `omarchy.bar` is
 used when `bar.id` is omitted or when a selected third-party bar cannot load.
-Panels, overlays, and menus are loaded when summoned. Plugins can set
-`keepLoaded: true` to survive between summons. First-party services are
-loaded at startup.
+Panels, overlays, and menus are loaded when summoned. Plugins can set the top-level manifest key `keepLoaded: true` to survive between summons, and to keep a service mounted across plugin hot-reload (so `omarchy.lock` is not destroyed while Hyprland still holds the session lock). First-party services are loaded at startup.
 
 Full schema: [`shell/services/PluginRegistry.qml`](../shell/services/PluginRegistry.qml).