Keep AppLibrary scans out of login shells (#6815)

* Keep AppLibrary scans out of login shells

A login shell sources the user's profile, and tools like mise touch
~/.local/share on activation. Quickshell's desktop-entry watcher monitors
that tree, so every scan retriggered another scan: a self-sustaining loop
that pinned ~20% of a core at idle. The scans only use bash builtins,
find, and sort, so they don't need the login environment.

Fixes #6806

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

* Pin the AppLibrary scans to non-login shells in tests

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

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

test/shell.d/app-search-test.sh

@@ -114,6 +114,13 @@ assert(
   'app library fallback icon index includes device icons'
 )
 
+assert(
+  appLibraryQml.includes('command: ["bash", "-c", root.hiddenEntryScanCommand()]') &&
+    appLibraryQml.includes('command: ["bash", "-c", root.iconIndexScanCommand()]') &&
+    !appLibraryQml.includes('"-lc"'),
+  'app library scans avoid login shells whose profile activation retriggers the desktop-entry watcher'
+)
+
 assert(
   /if \(active === "apps"\) \{[\s\S]*?rows\.sort\(function\(a, b\)/.test(menuQml),
   'apps menu enforces alphabetical display order after provider refreshes'