zsh: add zoxide/bat/delta, starship prompt config, extra history options; rewrite README

Bootstrap (zshrc-bootstrap.zsh):
- Add bat and zoxide to the cross-distro install loop
- Add git-delta install block (package is 'git-delta' on every PM but
  binary is 'delta', mirroring the starship/lazydocker pattern)
- Debian/Ubuntu compat: symlink batcat->bat and fdfind->fd into
  ~/.local/bin so zshrc integrations work under both names
- Bump ZSHRC_BOOTSTRAP_VERSION 2 -> 3 so existing machines re-run the
  bootstrap and auto-install the new tools

zshrc:
- Add setopts HIST_VERIFY, EXTENDED_HISTORY, AUTO_PUSHD,
  PUSHD_IGNORE_DUPS, PUSHD_SILENT
- Self-configuring tool integrations (all behind command -v guards):
  - zoxide: eval $(zoxide init zsh) for frecent 'z'/'zi' dir jumping
  - bat: alias cat->bat, BAT_THEME, colored MANPAGER via bat
  - delta: GIT_PAGER=delta for prettier git diff/log/show
- Extend the interactive auto-update block to also sync starship.toml
  to ~/.config/starship.toml (overwrite-if-changed, validated the
  same way as zshrc); keep the reproducible/self-configuring design
- Inverted hyperlink fix already landed in prior commit; no change
  here

starship.toml (new):
- Two-line prompt: directory + git status + cmd duration on line 1,
  arrow (red on error) on line 2; Nerd Font symbols, SSH host/user,
  Python/Node/Rust/Go/Java/Docker context blocks
- Validated clean with starship 1.21.1 (uses [nodejs], not [node])

README.md:
- Full rewrite: documents the design philosophy, all files, deps,
  integrations, history options, aliases, keybindings, the eza
  hyperlink workaround rationale, auto-update behavior, per-machine
  overrides, env vars, and helper functions

zsh/starship.toml

@@ -0,0 +1,101 @@
+# Starship prompt configuration - managed by the zshrc repo.
+# Local edits to ~/.config/starship.toml are overwritten on the next interactive
+# shell start (reproducible/self-configuring design). Uses Nerd Font symbols
+# (JetBrainsMono Nerd Font is installed by the tmux config).
+
+command_timeout = 1000
+add_newline = true
+
+# Two-line prompt:
+#   line 1: directory + git status + command duration
+#   line 2: the input arrow (red on error)
+format = """
+$directory\
+$git_branch\
+$git_status\
+$cmd_duration\
+$line_break\
+$character\
+"""
+
+[character]
+success_symbol = "[➜](bold green)"
+error_symbol = "[✗](bold red)"
+vimcmd_symbol = "[V](bold green)"
+
+[directory]
+truncation_length = 3
+truncate_to_repo = true
+style = "bold blue"
+read_only = " 󰌾"
+read_only_style = "red"
+repo_root_style = "bold cyan"
+
+[git_branch]
+symbol = " "
+style = "bold purple"
+format = "[$symbol$branch]($style) "
+
+[git_status]
+style = "bold red"
+conflicted = "=${count}"
+ahead = "⇡${count}"
+behind = "⇣${count}"
+diverged = "⇕↑${ahead_count}↓${behind_count}"
+untracked = "?${count}"
+stashed = " *${count}"
+modified = " !${count}"
+staged = " +${count}"
+renamed = " »${count}"
+deleted = " ✘${count}"
+format = '([$all_status$ahead_behind]($style) )'
+
+[cmd_duration]
+min_time = 2000
+format = "took [$duration](bold yellow) "
+
+[status]
+disabled = false
+format = '[$symbol]($style)'
+symbol = "✗ "
+success_symbol = ""
+style = "bold red"
+
+[username]
+show_always = false
+style_user = "bold yellow"
+style_root = "bold red"
+format = "[$user]($style)@"
+
+[hostname]
+ssh_only = true
+style = "bold green"
+format = "[$hostname]($style) "
+
+[python]
+symbol = " "
+format = '[${symbol}${pyenv_prefix}(${version})(\($virtualenv\))]($style) '
+
+[nodejs]
+symbol = " "
+format = "[$symbol($version)]($style) "
+
+[rust]
+symbol = " "
+format = "[$symbol($version)]($style) "
+
+[golang]
+symbol = " "
+format = "[$symbol($version)]($style) "
+
+[java]
+symbol = " "
+format = "[$symbol($version)]($style) "
+
+[docker_context]
+symbol = " "
+format = "[$symbol$context]($style) "
+
+[shell]
+disabled = true
+style = "bold cyan"