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/poke.fish

@@ -1,6 +1,22 @@
 # Copyright (C) 2026 Rootiest
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
+# SYNOPSIS
+#   poke <file> [file...]
+#
+# DESCRIPTION
+#   Creates files using touch, automatically creating any missing parent
+#   directories via _fish_mkdir_p with tree output.
+#
+# ARGUMENTS
+#   file  One or more file paths to create
+#
+# RETURNS
+#   0  Files created
+#   1  No file argument provided
+#
+# EXAMPLE
+#   poke ~/projects/new/src/main.fish
 function poke --description 'touch with automatic parent directory creation'
     if test (count $argv) -eq 0
         echo (set_color red)"poke: no file specified"(set_color normal) >&2