feature: Add begin/end line singlechar insertion and static cursor option

- Introduce InsertCharBegin and InsertCharEnd commands
to insert a character at the beginning or end of the line (<Leader>I and <Leader>A).
- Add configuration variables for customizable mappings:
 - g:singlechar_map_insert_begin
 - g:singlechar_map_insert_end
- Implement GetInsertCommand() and DoSingleChar() in autoload/singlechar.vim
to support new modes and static cursor feature.
- Add g:singlechar_static_cursor option:
    when enabled, cursor returns to its original position after insertion.

autoload/singlechar.vim

@@ -19,11 +19,10 @@ export def InsertChar(mode: string, count: number, input_char: string = ''): voi
         return
     endif
 
-    # Determine whether to insert before (i) or after (a) cursor
+    var insert_command = GetInsertCommand(mode)
-    var insert_command = (mode ==# 'at') ? 'i' : 'a'
     var insert_text = repeat(first_char, (count == 0) ? 1 : count)
 
-    execute 'normal! ' .. insert_command .. insert_text .. "\<Esc>"
+    DoSingleChar(insert_command, insert_text, g:singlechar_static_cursor)
     
     # Save last used values
     g:last_singlechar_key = first_char
@@ -38,6 +37,31 @@ export def InsertChar(mode: string, count: number, input_char: string = ''): voi
     endif
 enddef
 
+def GetInsertCommand(mode: string): string
+    if mode ==# 'at'
+        return 'i'
+    elseif mode ==# 'after'
+        return 'a'
+    elseif mode ==# 'begin'
+        return 'I'
+    elseif mode ==# 'end'
+        return 'A'
+    else
+        return 'i'
+    endif
+enddef
+
+def DoSingleChar(command: string, text: string, resetCursor: number): void
+    var pos = getpos('.')
+    execute 'normal! ' .. command .. text .. "\<Esc>"
+    if resetCursor == 1
+        if (command ==# 'i')
+            pos[2] = pos[2] + 1
+        endif
+        setpos('.', pos)
+    endif
+enddef
+
 def g:RepeatSingleChar(): void
     if g:last_singlechar_key != ''
         call InsertChar(g:last_singlechar_mode, g:last_singlechar_count, g:last_singlechar_key)

plugin/singlechar.vim

@@ -30,15 +30,32 @@ if !exists('g:singlechar_map_insert_after')
   g:singlechar_map_insert_after = '<Leader>a'
 endif
 
+# Mapping to insert a character at the endline
+if !exists('g:singlechar_map_insert_end')
+  g:singlechar_map_insert_end = '<Leader>A'
+endif
+
+# Mapping to insert a character at the startline
+if !exists('g:singlechar_map_insert_begin')
+  g:singlechar_map_insert_begin = '<Leader>I'
+endif
+
 # Prompt message shown when waiting for character input
 if !exists('g:singlechar_prompt')
   g:singlechar_prompt = 'Press the character to insert - Press Esc to cancel...'
 endif
 
+#Toggle static cursor
+if !exists('g:singlechar_static_cursor')
+  g:singlechar_static_cursor = 0
+endif
+
+# toggle warnign
 if !exists('g:singlechar_keylen_warning')
   g:singlechar_keylen_warning = 1
 endif
 
+# warning message
 if !exists('g:singlechar_warning_message')
   g:singlechar_warning_message = 'Only the first character will be taken: {char}'
 endif
@@ -54,6 +71,8 @@ g:last_singlechar_count = 1
 nnoremap <Plug>(singlechar-repeat) :call g:RepeatSingleChar()<CR>
 
 # Direct command implementations
+command! -count=1 -nargs=? InsertCharBegin singlechar.InsertChar('begin', <count>, <q-args>)
+command! -count=1 -nargs=? InsertCharEnd singlechar.InsertChar('end', <count>, <q-args>)
 command! -count=1 -nargs=? InsertCharAt singlechar.InsertChar('at', <count>, <q-args>)
 command! -count=1 -nargs=? InsertCharAfter singlechar.InsertChar('after', <count>, <q-args>)
 
@@ -61,6 +80,8 @@ command! -count=1 -nargs=? InsertCharAfter singlechar.InsertChar('after', <count
 if !exists('g:singlechar_no_mappings')
     execute 'nnoremap <expr> <silent> ' .. g:singlechar_map_insert_at .. ' ":<C-u>InsertCharAt " .. v:count1 .. "<CR>"' 
     execute 'nnoremap <expr> <silent> ' .. g:singlechar_map_insert_after .. ' ":<C-u>InsertCharAfter " .. v:count1 .. "<CR>"'
+    execute 'nnoremap <expr> <silent> ' .. g:singlechar_map_insert_begin .. ' ":<C-u>InsertCharBegin " .. v:count1 .. "<CR>"'
+    execute 'nnoremap <expr> <silent> ' .. g:singlechar_map_insert_end .. ' ":<C-u>InsertCharEnd " .. v:count1 .. "<CR>"'
 endif
 
 # Usage: