refactor: migrate to role-based variable management and blockinfile config

dotfiles/starship/.config/starship/config.toml

@@ -1,24 +0,0 @@
-$formatters
-format = """
-[─](bold green)
-[❯](bold green) """
-add_newline = true
-
-[character]
-success_symbol = "[❯](bold green)"
-error_symbol = "[❯](bold red)"
-
-[directory]
-home_symbol = "~"
-truncation_length = 3
-truncate_to_repo = true
-
-[git]
-branch_symbol = " "
-stash_count_symbol = " "
-format = "on [$symbol$branch]($style)$completions"
-style = "bold purple"
-
-[docker_context]
-format = "via [$symbol$context]($style) "
-style = "blue bold"