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/gip.fish

@@ -1,7 +1,15 @@
 # Copyright (C) 2026 Rootiest
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
-# Show all public IP addresses
+# SYNOPSIS
+#   gip
+#
+# DESCRIPTION
+#   Fetches and prints both the public IPv4 and IPv6 addresses using
+#   icanhazip.com. Shows "Not detected" for any address that times out.
+#
+# EXAMPLE
+#   gip
 function gip --description 'Show all public IP addresses'
     echo -n "IPv4: "
     curl -4 -s --max-time 2 https://icanhazip.com || echo "Not detected"