feat(ui): add DiagnosticBadge component for terminal output

crates/cli/src/ui/badges.rs

@@ -0,0 +1,79 @@
+use std::fmt;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum DiagnosticCategory {
+    Success,
+    Info,
+    Warning,
+    Error,
+}
+
+impl DiagnosticCategory {
+    pub fn icon(&self) -> &'static str {
+        match self {
+            DiagnosticCategory::Success => "✔",
+            DiagnosticCategory::Info => "ℹ",
+            DiagnosticCategory::Warning => "⚠",
+            DiagnosticCategory::Error => "✖",
+        }
+    }
+
+    pub fn fallback(&self) -> &'static str {
+        match self {
+            DiagnosticCategory::Success => "[SUCCESS]",
+            DiagnosticCategory::Info => "[INFO]",
+            DiagnosticCategory::Warning => "[WARN]",
+            DiagnosticCategory::Error => "[ERROR]",
+        }
+    }
+
+    pub fn color_code(&self) -> &'static str {
+        match self {
+            DiagnosticCategory::Success => "\x1b[32m",
+            DiagnosticCategory::Info => "\x1b[34m",
+            DiagnosticCategory::Warning => "\x1b[33m",
+            DiagnosticCategory::Error => "\x1b[31m",
+        }
+    }
+}
+
+pub struct DiagnosticBadge {
+    pub category: DiagnosticCategory,
+    pub supports_unicode: bool,
+}
+
+impl DiagnosticBadge {
+    pub fn new(category: DiagnosticCategory, supports_unicode: bool) -> Self {
+        Self {
+            category,
+            supports_unicode,
+        }
+    }
+
+    pub fn format_message(&self, message: &str) -> String {
+        let badge_text = if self.supports_unicode {
+            self.category.icon()
+        } else {
+            self.category.fallback()
+        };
+
+        format!(
+            "{}{} \x1b[0m{}",
+            self.category.color_code(),
+            badge_text,
+            message
+        )
+    }
+}
+
+impl fmt::Display for DiagnosticBadge {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let badge_text = if self.supports_unicode {
+            self.category.icon()
+        } else {
+            self.category.fallback()
+        };
+
+        write!(f, "{}{}\x1b[0m", self.category.color_code(), badge_text)
+    }
+}