feat: move Settings out of Files into its own searchable app with categories

template/docs/gui-apps.md

@@ -886,12 +886,18 @@ admin_only = false
 
 [launch]
 pass_home_dir = true
+
+# Optional: list the app in the Settings app
+[settings]
+category = "Devices"
+description = "One line shown under the name"
+keywords = "extra words search should match"
 ```
 
 **Categories:** `Applications`, `Internet`, `System`, `Games`
 
 The desktop scans `0:/apps/` at startup and builds one catalog used by the
-application menu, launcher search, and the Apps and Settings virtual folders.
+application menu, launcher search, the Files Apps folder and the Settings app.
 `app.id` must be unique; when omitted, the containing directory name is used.
 The `binary` field names an executable in that app's bundle.
 
@@ -902,6 +908,14 @@ launcher. Set `desktop.admin_only` to hide the item from non-administrator
 users. `launch.pass_home_dir` controls whether the current user's home path is
 passed as the executable's first argument.
 
+The Settings app (`0:/apps/settings/settings.elf`) lists every `settings`
+section item, plus any other app whose manifest has a `[settings]` table.
+`settings.category` files it under `Personalization`, `Network`, `Devices`,
+`Time & Language`, `Accounts`, `Privacy & Security` or `System` (the default);
+any other name becomes a category of its own. Search matches the name, the
+category, `settings.description` (up to 63 bytes) and `settings.keywords` (up
+to 127 bytes).
+
 ---
 
 ## Build System