Refactor monorepo structure and replace hardcoded colors

Add TypeScript project references, update ESLint configs to support
ESM modules, and introduce brand semantic color tokens across the web
app. Add comprehensive documentation for architecture, API reference,
development setup, and user guide.

apps/web/eslint.config.mjs

@@ -1,6 +1,10 @@
 import { defineConfig, globalIgnores } from "eslint/config";
 import nextVitals from "eslint-config-next/core-web-vitals";
 import nextTs from "eslint-config-next/typescript";
+import { fileURLToPath } from "url";
+import path from "path";
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 const eslintConfig = defineConfig([
   ...nextVitals,
@@ -14,6 +18,11 @@ const eslintConfig = defineConfig([
     "next-env.d.ts",
   ]),
   {
+    languageOptions: {
+      parserOptions: {
+        tsconfigRootDir: path.resolve(__dirname),
+      },
+    },
     rules: {
       // Allow _-prefixed parameters and variables to signal intentionally unused.
       "@typescript-eslint/no-unused-vars": [