docs(functions): standardize all function doc blocks to UNIX man-page style

Replace all ad-hoc inline comments between license headers and function
declarations with consistent SYNOPSIS / DESCRIPTION / ARGUMENTS / RETURNS /
EXAMPLE blocks across all 99 project-owned functions/ files. No executable
logic, variable names, or exit codes were modified.

Completes Task #6 from AGENTS.md (Retroactive Function Documentation
Standardization).

functions/screensleep.fish

@@ -1,7 +1,15 @@
 # Copyright (C) 2026 Rootiest
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
-# Turn off the display using KDE PowerDevil
+# SYNOPSIS
+#   screensleep
+#
+# DESCRIPTION
+#   Turns off the display after a 1-second delay by invoking the KDE
+#   PowerDevil "Turn Off Screen" global shortcut via busctl.
+#
+# EXAMPLE
+#   screensleep
 function screensleep --description 'Turn off the display using KDE PowerDevil'
     # Optional: 1-second delay to ensure no keystrokes wake it immediately
     sleep 1