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)

shell/README.md

@@ -86,8 +86,12 @@ Only one `bar` plugin is active at a time. Missing or invalid selections fall
 back to the built-in `omarchy.bar`, so users always have a safe path home.
 Panels, overlays, and menus are loaded when summoned. Plugins that need
 to outlive a single summon can set `keepLoaded: true` (e.g. the image
-picker keeps its overlay window mounted between summons). First-party
-services are loaded at startup.
+picker keeps its overlay window mounted between summons). The same flag
+keeps a service mounted across plugin hot-reload, so tearing down a
+changed bar widget cannot destroy `omarchy.lock` while Hyprland still
+holds the session lock. The kept instance is not replaced, so code
+changes to a `keepLoaded` service itself only take effect on a shell
+restart. First-party services are loaded at startup.
 
 The full schema lives in `services/PluginRegistry.qml`.