Fix: bundle output to extension/dist/content/, update manifest path

The esbuild outdir was relative to cwd, so it landed at project root
(dist/content/) on a project-root build, not under the extension dir.
Fix:
- esbuild writes to extension/dist/content/
- manifest.json content_scripts.js → dist/content/index.js
- Keeps the extension self-contained so Chrome --load-extension works
  without any external files

esbuild.config.mjs

@@ -3,7 +3,9 @@ import * as esbuild from 'esbuild';
 import { existsSync, mkdirSync } from 'node:fs';
 
 const isWatch = process.argv.includes('--watch');
-const outdir = 'dist/content';
+// Bundle lives under extension/dist/content/ so Chrome can load the
+// extension directory without needing any files outside it.
+const outdir = 'extension/dist/content';
 
 if (!existsSync(outdir)) mkdirSync(outdir, { recursive: true });
 

extension/manifest.json

@@ -25,7 +25,7 @@
     {
       "matches": ["*://beat-battle.net/*"],
       "run_at": "document_idle",
-      "js": ["content/index.js"],
+      "js": ["dist/content/index.js"],
       "css": ["content/inject.css"]
     }
   ],