refactor: trim configuration and drop unused plugins

- Merge sunbather dark/light into one background-aware color scheme
- Fold uninstall.sh into install.sh as a subcommand; drop clone logic
- Inline bash_tools/ helpers; remove fct and odict
- Remove TPM, tmux-sensible, and tmux-fuzzback; tmux has no plugins now
- Remove vim-repeat, vim-fugitive, vim-gitgutter, vim-tmux-navigator,
  and moonfly; everforest is the default dark theme
- Fetch vim-plug via git instead of curl; require git, not curl
- Guard termguicolors on Windows consoles without VT support and set
  nomore before the vimrc loads so headless installs cannot hang
- Fall back to sunbather when a color scheme fails to load, without
  overwriting the saved preference
- Append config/vim to runtimepath so netrw stops writing into the repo
- Fix .editorconfig Python indent; trim .gitignore; update CI and README

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NBfsAH6iJg9inkNLKq11YC

config/vim/autoload/theme.vim

@@ -1,7 +1,7 @@
 let s:path = get(g:, 'vim_dir', expand('~/.vim')) . '/theme.json'
 let s:defaults = {
       \ 'background': 'dark',
-      \ 'dark': {'theme': 'moonfly', 'transparent': v:false},
+      \ 'dark': {'theme': 'everforest', 'transparent': v:false},
       \ 'light': {'theme': 'PaperColor', 'transparent': v:false}}
 let s:config = deepcopy(s:defaults)
 let s:applying = v:false
@@ -60,11 +60,15 @@ endfunction
 
 function! theme#apply(name) abort
   let l:background = &background
-  let l:name = s:Available(a:name) ? a:name
-        \ : (l:background ==# 'dark' ? 'sunbather_dark' : 'sunbather_light')
+  let l:name = s:Available(a:name) ? a:name : 'sunbather'
   let s:applying = v:true
   try
     execute 'colorscheme ' . l:name
+  catch
+    " A scheme that fails to load (for example, one that needs true color in a
+    " terminal without it) must not leave Vim without a color scheme. The
+    " saved preference is kept so the next capable session restores it.
+    colorscheme sunbather
   finally
     let s:applying = v:false
   endtry
@@ -100,9 +104,6 @@ function! theme#onColorScheme(name) abort
   if s:applying
     return
   endif
-  if a:name !~# '^sunbather_' && index(['everforest', 'moonfly', 'PaperColor'], a:name) < 0
-    return
-  endif
   let s:config.background = &background
   let s:config[&background].theme = a:name
   call s:ApplyTransparency()