Unify installer colors with vim/shell palette and clean up output

- Replace BLUE/CYAN/CYAN_BOLD with TEAL/TEAL_BOLD (#2CB494) to match
  the primary accent used across vim, zsh prompt, tmux, and fzf
- Update BLUE (#0C48CC -> #4068D4) then merge into TEAL
- Update RED (#F40404 -> #F88C14) to match vim/shell error orange
- Rename GREEN to grey-blue (#7290B8) for [PASS] messages
- Format all raw echo output with log functions or log_quote
- Suppress sudo prompt when credentials are already cached
- Add missing log_pass to 22-zsh.sh and 23-stow.sh
- Convert raw 'already installed' echos to log_skip (7 scripts)
- Pipe SSH key and mise output through log_quote
- Suppress noisy bat cache and mise WARN output
- Match fastfetch colors to palette (teal logo, grey-blue keys)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

install.d/99-fastfetch.sh

@@ -8,5 +8,9 @@
 # Skip in Codespaces (cosmetic only)
 [[ "$DOTS_ENV" == "codespaces" ]] && { log_skip "Codespaces"; return 0; }
 
-fastfetch --pipe false
+fastfetch --pipe false \
+    --logo-color-1 "38;2;44;180;148" \
+    --color-title "38;2;44;180;148" \
+    --color-keys "38;2;114;144;184" \
+    --color-separator "38;2;128;128;128"