feat: improve depot UX and packaging workflow

- add shared terminal UI helpers for colored info/warn/success logs and yes/no prompts
- add Python build backend (PEP 517/setup.py wheel build + install) and expose python in interactive spec creation
- expand spec/build flags (post_configure, make phase targets/dirs, configure_file, no_strip, no_compress_man)
- support split-output staging with internal .depot output dirs, shell helpers (haul/subdestdir), and per-output deps/provides overrides
- improve staging with ELF auto-strip and zstd manpage compression (with opt-out flags)
- enforce runtime deps before install and support legacy lifecycle hook script names
- improve manual source handling with files/urls lists and stricter validation

src/ui.rs

@@ -0,0 +1,135 @@
+//! Terminal UI helpers (colors + prompts).
+
+use anyhow::{Context, Result};
+use std::io::{self, IsTerminal, Write};
+
+#[derive(Clone, Copy)]
+enum Stream {
+    Stdout,
+    Stderr,
+}
+
+fn colors_enabled(stream: Stream) -> bool {
+    if std::env::var_os("NO_COLOR").is_some() {
+        return false;
+    }
+    if matches!(std::env::var("TERM").as_deref(), Ok("dumb")) {
+        return false;
+    }
+
+    match stream {
+        Stream::Stdout => io::stdout().is_terminal(),
+        Stream::Stderr => io::stderr().is_terminal(),
+    }
+}
+
+fn paint(stream: Stream, text: &str, color_code: &str) -> String {
+    if colors_enabled(stream) {
+        format!("\x1b[{}m{}\x1b[0m", color_code, text)
+    } else {
+        text.to_string()
+    }
+}
+
+fn label(stream: Stream, text: &str, color_code: &str) -> String {
+    format!("[{}]", paint(stream, text, color_code))
+}
+
+pub fn info(message: impl AsRef<str>) {
+    println!(
+        "{} {}",
+        label(Stream::Stdout, "INFO", "36"),
+        message.as_ref()
+    );
+}
+
+pub fn success(message: impl AsRef<str>) {
+    println!("{} {}", label(Stream::Stdout, "OK", "32"), message.as_ref());
+}
+
+pub fn warn(message: impl AsRef<str>) {
+    eprintln!(
+        "{} {}",
+        label(Stream::Stderr, "WARN", "33"),
+        message.as_ref()
+    );
+}
+
+#[macro_export]
+macro_rules! log_info {
+    ($($arg:tt)*) => {
+        $crate::ui::info(format!($($arg)*))
+    };
+}
+
+#[macro_export]
+macro_rules! log_ok {
+    ($($arg:tt)*) => {
+        $crate::ui::success(format!($($arg)*))
+    };
+}
+
+#[macro_export]
+macro_rules! log_warn {
+    ($($arg:tt)*) => {
+        $crate::ui::warn(format!($($arg)*))
+    };
+}
+
+fn parse_yes_no_input(input: &str, default_yes: bool) -> Option<bool> {
+    let trimmed = input.trim().to_ascii_lowercase();
+    if trimmed.is_empty() {
+        return Some(default_yes);
+    }
+    match trimmed.as_str() {
+        "y" | "yes" => Some(true),
+        "n" | "no" => Some(false),
+        _ => None,
+    }
+}
+
+pub fn prompt_yes_no(prompt: &str, default_yes: bool) -> Result<bool> {
+    let default_hint = if default_yes { "Y/n" } else { "y/N" };
+    loop {
+        print!(
+            "{} {} [{}] ",
+            label(Stream::Stdout, "?", "35"),
+            prompt,
+            default_hint
+        );
+        io::stdout()
+            .flush()
+            .context("Failed to flush prompt to stdout")?;
+
+        let mut input = String::new();
+        io::stdin()
+            .read_line(&mut input)
+            .context("Failed to read user input from stdin")?;
+
+        if let Some(answer) = parse_yes_no_input(&input, default_yes) {
+            return Ok(answer);
+        }
+
+        warn("Please answer with 'y' or 'n'.");
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::parse_yes_no_input;
+
+    #[test]
+    fn parse_yes_no_defaults() {
+        assert_eq!(parse_yes_no_input("", true), Some(true));
+        assert_eq!(parse_yes_no_input("", false), Some(false));
+    }
+
+    #[test]
+    fn parse_yes_no_values() {
+        assert_eq!(parse_yes_no_input("y", false), Some(true));
+        assert_eq!(parse_yes_no_input("yes", false), Some(true));
+        assert_eq!(parse_yes_no_input("N", true), Some(false));
+        assert_eq!(parse_yes_no_input("no", true), Some(false));
+        assert_eq!(parse_yes_no_input("maybe", true), None);
+    }
+}