docs(functions): merge remaining manual prose into function headers

Folds the last seven manual entries whose description exceeded their header
back into the source-of-truth comment blocks: config-settings (Sponge/Paths
page detail, list-value parsing, width tiers, navigation keys), fish-deps
(install-method priority, dependency tiers), logs (fzf keybindings, ov
viewer behavior), kitty-logging (symlink wording, C5 inert-vs-uninstalled),
config-update (exec fish reload), yt-dlp (C1 guard). Drops duplicate example
lines left by the previous merge.

functions/fish-deps.fish

@@ -8,8 +8,26 @@
 #   fish-deps [status|install|update|sync]
 #
 # DESCRIPTION
-#   Manages fish shell dependencies by dispatching to subcommand handlers.
-#   Defaults to status when no subcommand is given.
+#   Unified command for managing all tools this configuration depends on,
+#   dispatching to subcommand handlers. Defaults to status when no subcommand
+#   is given.
+#
+#   Install method priority (highest to lowest):
+#     1. git+cargo source build (fish shell itself)
+#     2. cargo (Rust tools — gets latest crate version)
+#     3. system PM (paru/apt/brew/etc.)
+#     4. git clone (fzf)
+#     5. curl installer (starship, fisher, uv)
+#
+#   When multiple methods are available you are prompted to choose.
+#
+#   Dependencies are grouped into three tiers:
+#
+#     Required      fish, fzf, zoxide
+#     Integrations  wakatime, tailscale
+#     Recommended   cargo, starship, uv, direnv, paru, yay, eza, lsd, bat,
+#                   btop, dust, duf, prettyping, ov, ripgrep, lazygit,
+#                   lazydocker, trash, kitty, wezterm, python3, yt-dlp
 #
 # ARGUMENTS
 #   status   Report installed/missing deps (default)