feat: add SQL syntax highlighting in query editor

src/main.rs

@@ -1,6 +1,7 @@
 mod app;
 mod connection;
 mod db;
+mod sql;
 
 use std::{error::Error, io::IsTerminal, path::Path, process::ExitCode};
 
@@ -45,6 +46,8 @@ Navigation:
   appears in the rows/schema border. Read errors appear above the query editor.
   In the query editor, type SQL directly; Enter inserts a newline. Arrow keys,
   Home/End, Backspace/Delete, Ctrl-U (clear), and multiline pasting are supported.
+  SQL syntax colors follow the connected database's PostgreSQL/SQLite dialect,
+  including quoted identifiers, literals, and multiline comments/strings as you type.
   F5 / Ctrl-Enter executes one SELECT/CTE on the current connection, showing up
   to 100 rows below. Results report truncation; use SQL LIMIT/OFFSET for more.
   Failed queries keep the previous results. Opening a relation restores browsing