feat(deps): add Optional/Terminal Emulator tiers, fix docker prompt hang and ov install path

Reworks fish-deps' dependency classification from three tiers to five:
Required, Recommended, Optional, Terminal Emulators, and Integrations.

- Add an Optional tier for single-purpose wrapper conveniences that only
  matter if you already use that specific tool (btop, dust, duf,
  prettyping, go, lazygit, lazydocker, docker, yt-dlp, screen). Skipped by
  `fish-deps install`/`sync` by default.
- Split kitty/wezterm into their own Terminal Emulators tier, since only
  the one matching $TERM is ever relevant to a given user.
- Add --optional, --terminals, and --all flags to `install`/`sync` to
  opt back into the skipped tiers, with a summary of how many were
  skipped and which flag restores them.
- Fix `_fish_deps_status` marking missing Integrations as critical (red)
  the same as Required — only Required is red now; Recommended stays
  yellow, everything else renders as a neutral dim note.

Also fixes two bugs surfaced during dependency testing on a fresh
install:

- `fish_right_prompt` called `docker context show` on every prompt with
  no `type -q docker` guard, unlike every other optional integration in
  this config — on a system without docker this printed a visible
  "Unknown command: docker" block on every single prompt render. Added
  the missing guard, and hardened the `ld` wrapper with explicit
  docker/lazydocker presence checks.
- `ov`'s catalog entry offered `cargo install ov` as its preferred
  install method, but crates.io's `ov` is an unrelated crate, not the
  noborus/ov pager — cargo would silently install the wrong package.
  Removed the cargo path; `ov` now prefers `go install
  github.com/noborus/ov@latest` (ahead of the system PM) when go is
  available, since not all distros package `ov` in their base repos,
  and falls back to the system PM otherwise.

functions/_fish_deps_status.fish

@@ -6,7 +6,8 @@
 #
 # DESCRIPTION
 #   Prints a colored installed/missing status report for all managed fish shell
-#   dependencies, grouped by tier (required, integrations, recommended).
+#   dependencies, grouped by tier (required, recommended, optional, terminal
+#   emulators, integrations).
 #
 # EXAMPLE
 #   _fish_deps_status
@@ -31,18 +32,23 @@ function _fish_deps_status
             set_color green; echo -n " ✓ "; set_color normal
             echo -n "$bin "
             set_color brblack; echo "(Found at "(__fish_real_command $bin)")"; set_color normal
+        else if test "$tier" = req
+            set_color red; echo -n " ✗ "; set_color normal
+            echo -n "$bin "
+            set_color brblack; echo "(Not installed)"; set_color normal
         else if test "$tier" = rec
             set_color yellow; echo -n " ⚠ "; set_color normal
             echo -n "$bin "
             set_color brblack; echo "(Not installed)"; set_color normal
         else
-            set_color red; echo -n " ✗ "; set_color normal
+            # opt / term / int: absence is expected and not alarming
+            set_color brblack; echo -n " – "; set_color normal
             echo -n "$bin "
             set_color brblack; echo "(Not installed)"; set_color normal
         end
     end
 
-    for tier_label in "Required Dependencies:req" "Integrations:int" "Recommended Dependencies:rec"
+    for tier_label in "Required Dependencies:req" "Recommended Dependencies:rec" "Optional Dependencies:opt" "Terminal Emulators:term" "Integrations:int"
         set -l label (string split : $tier_label)[1]
         set -l tier  (string split : $tier_label)[2]
         set_color cyan; echo $label; set_color normal