refactor: add colors module for terminal output

crates/plotnik-lib/src/colors.rs

@@ -0,0 +1,57 @@
+//! ANSI color codes for terminal output.
+//!
+//! Four semantic colors with orthogonal dim modifier:
+//! - Blue: Definition names, keys, type names
+//! - Green: String literals, terminal markers
+//! - Dim: Structure, nav, effects, metadata
+//! - Reset: Return to default
+
+/// ANSI color palette for CLI output.
+///
+/// Designed for jq-inspired colorization that works in both light and dark themes.
+/// Uses only standard 16-color ANSI codes (no RGB).
+#[derive(Clone, Copy, Debug)]
+pub struct Colors {
+    pub blue: &'static str,
+    pub green: &'static str,
+    pub dim: &'static str,
+    pub reset: &'static str,
+}
+
+impl Default for Colors {
+    fn default() -> Self {
+        Self::OFF
+    }
+}
+
+impl Colors {
+    /// Colors enabled (ANSI escape codes).
+    pub const ON: Self = Self {
+        blue: "\x1b[34m",
+        green: "\x1b[32m",
+        dim: "\x1b[2m",
+        reset: "\x1b[0m",
+    };
+
+    /// Colors disabled (empty strings).
+    pub const OFF: Self = Self {
+        blue: "",
+        green: "",
+        dim: "",
+        reset: "",
+    };
+
+    /// Create colors based on enabled flag.
+    pub fn new(enabled: bool) -> Self {
+        if enabled {
+            Self::ON
+        } else {
+            Self::OFF
+        }
+    }
+
+    /// Check if colors are enabled.
+    pub fn is_enabled(&self) -> bool {
+        !self.blue.is_empty()
+    }
+}

crates/plotnik-lib/src/lib.rs

@@ -18,6 +18,7 @@
 
 pub mod analyze;
 pub mod bytecode;
+pub mod colors;
 pub mod compile;
 pub mod diagnostics;
 pub mod emit;
@@ -32,6 +33,7 @@ pub mod typegen;
 /// Fatal errors (like fuel exhaustion) use the outer `Result`.
 pub type PassResult<T> = std::result::Result<(T, Diagnostics), Error>;
 
+pub use colors::Colors;
 pub use diagnostics::{Diagnostics, DiagnosticsPrinter, Severity, Span};
 pub use query::{Query, QueryBuilder};
 pub use query::{SourceId, SourceMap};