Put config files under /config

[ForestMars]

Housekeeping: Let's clean up the root directory and move all the config files into /config.

Here's how (should be mostly correct)

File	Steps to Update
vite.config.ts	In vite.config.ts, add: configFile: path.resolve(__dirname, 'config/vite.config.ts') in the export to make Vite load from /config.
tsconfig.json	In package.json, update the tsc script: tsc --project ./config/tsconfig.json.
tsconfig.node.json	Update any build scripts in package.json to: tsc --project ./config/tsconfig.node.json.
tsconfig.app.json	Update any build scripts in package.json to: tsc --project ./config/tsconfig.app.json.
tailwind.config.js	In postcss.config.js or postcss.config.cjs, update the path to: require('./config/tailwind.config.js').
.eslintrc.js	In package.json, add: "eslintConfig": { "extends": "./config/.eslintrc.js" } to point ESLint to /config/.eslintrc.js.
postcss.config.js	Change the path in postcss.config.js to: require('./config/tailwind.config.js').
postcss.config.cjs	Change the path in postcss.config.cjs to: require('./config/tailwind.config.js').
vitest.config.ts	Update any vitest.config.ts to reference config/vitest.config.ts if used in your tests.