chore(deps): drop better-sqlite3 and its desktop packaging support

The SQLite write into OpenCode's database was the only consumer of
better-sqlite3 in the repository. Everything that existed to ship its native
binary went with it:

- the dependency in @openchamber/web and @openchamber/electron
- the afterPack hook staging better_sqlite3.node into app.asar.unpacked
- a dedicated @electron/rebuild pass (onlyModules) and its binary assertion,
  so desktop packaging now runs one native rebuild instead of two
- the bundler external entry and the AppImage required-native-module check

Desktop packaging, the AppImage verification tests, and the extension bundle
were re-validated after a clean reinstall, so no stale module could satisfy a
missed import.

packages/electron/scripts/after-pack.cjs

@@ -5,23 +5,6 @@ module.exports = (context) => {
   const resourcesPath = context.electronPlatformName === 'darwin'
     ? path.join(context.appOutDir, `${context.packager.appInfo.productFilename}.app`, 'Contents', 'Resources')
     : path.join(context.appOutDir, 'resources');
-  const betterSqliteDir = path.dirname(require.resolve('better-sqlite3/package.json'));
-  const betterSqliteBinary = path.join(betterSqliteDir, 'build', 'Release', 'better_sqlite3.node');
-  if (!fs.existsSync(betterSqliteBinary)) {
-    throw new Error(`Missing rebuilt better-sqlite3 binary at ${betterSqliteBinary}`);
-  }
-  const packagedBetterSqliteBinary = path.join(
-    resourcesPath,
-    'app.asar.unpacked',
-    'node_modules',
-    'better-sqlite3',
-    'build',
-    'Release',
-    'better_sqlite3.node',
-  );
-  fs.mkdirSync(path.dirname(packagedBetterSqliteBinary), { recursive: true });
-  fs.copyFileSync(betterSqliteBinary, packagedBetterSqliteBinary);
-
   if (context.electronPlatformName !== 'darwin') return;
 
   const sourceAssetsPath = path.join(__dirname, '..', 'resources', 'icons', 'Assets.car');