feat(brand): redesign logo with bold box-drawing ASCII art; bump v0.1.3

Replace the simple ASCII logo with a bold 'GAI' box-drawing font
that renders cleanly in modern terminals. Fix version to v0.1.3
across all files (brand, cli, index, package.json).

index.ts

@@ -1,7 +1,7 @@
 #!/usr/bin/env bun
 
 // gai — AI-powered git commit and PR helper
-// v0.2.0
+// v0.1.3
 
 import { runCLI, registerCommands, formatHelp, type CommandDef, type ParsedArgs } from "./src/cli";
 import { handleCommit } from "./src/commands/commit";
@@ -239,7 +239,7 @@ async function showMenu(): Promise<number> {
         process.stdin.setRawMode(wasRaw === true);
         process.stdin.pause();
         process.stdout.write("\x1b[2J\x1b[H");
-        console.log("gai v0.2.0");
+        console.log("gai v0.1.3");
         return 0;
       }
       if (lower === "q") {