Add authentication system with next-auth (CredentialsProvider + JWT)

- Login page with email/password
- Auth middleware (proxy) protecting all routes
- Seed endpoint for admin user creation (admin@optiquestock.com / admin123)
- Session provider wrapping root layout
- User info + logout button in header
- Updated POS sales route to track authenticated user

bun.lock

@@ -42,6 +42,7 @@
         "@tanstack/react-query": "^5.82.0",
         "@tanstack/react-table": "^8.21.3",
         "@types/qrcode": "^1.5.6",
+        "bcryptjs": "^3.0.3",
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
         "cmdk": "^1.1.1",
@@ -76,6 +77,7 @@
       },
       "devDependencies": {
         "@tailwindcss/postcss": "^4",
+        "@types/bcryptjs": "^3.0.0",
         "@types/react": "^19",
         "@types/react-dom": "^19",
         "bun-types": "^1.3.4",
@@ -676,6 +678,8 @@
 
     "@tybys/wasm-util": ["@tybys/wasm-util@0.10.1", "", { "dependencies": { "tslib": "^2.4.0" } }, "sha512-9tTaPJLSiejZKx+Bmog4uSubteqTvFrVrURwkmHixBo0G4seD0zUxp98E1DzUBJxLQ3NPwXrGKDiVjwx/DpPsg=="],
 
+    "@types/bcryptjs": ["@types/bcryptjs@3.0.0", "", { "dependencies": { "bcryptjs": "*" } }, "sha512-WRZOuCuaz8UcZZE4R5HXTco2goQSI2XxjGY3hbM/xDvwmqFWd4ivooImsMx65OKM6CtNKbnZ5YL+YwAwK7c1dg=="],
+
     "@types/d3-array": ["@types/d3-array@3.2.2", "", {}, "sha512-hOLWVbm7uRza0BYXpIIW5pxfrKe0W+D5lrFiAEYR+pb6w3N2SwSMaJbXdUfSEv+dT4MfHBLtn5js0LAWaO6otw=="],
 
     "@types/d3-color": ["@types/d3-color@3.1.3", "", {}, "sha512-iO90scth9WAbmgv7ogoq57O9YpKmFBbmoEoCHDB2xMBY0+/KVrqAaCDyCE16dUspeOvIxFFRI+0sEtqDqy2b4A=="],
@@ -832,6 +836,8 @@
 
     "baseline-browser-mapping": ["baseline-browser-mapping@2.9.15", "", { "bin": { "baseline-browser-mapping": "dist/cli.js" } }, "sha512-kX8h7K2srmDyYnXRIppo4AH/wYgzWVCs+eKr3RusRSQ5PvRYoEFmR/I0PbdTjKFAoKqp5+kbxnNTFO9jOfSVJg=="],
 
+    "bcryptjs": ["bcryptjs@3.0.3", "", { "bin": { "bcrypt": "bin/bcrypt" } }, "sha512-GlF5wPWnSa/X5LKM1o0wz0suXIINz1iHRLvTS+sLyi7XPbe5ycmYI3DlZqVGZZtDgl4DmasFg7gOB3JYbphV5g=="],
+
     "brace-expansion": ["brace-expansion@1.1.12", "", { "dependencies": { "balanced-match": "^1.0.0", "concat-map": "0.0.1" } }, "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg=="],
 
     "braces": ["braces@3.0.3", "", { "dependencies": { "fill-range": "^7.1.1" } }, "sha512-yQbXgO/OSZVD2IsiLlro+7Hf6Q18EJrKSEsdoMzKePKXct3gvD8oLcOQdIzGupr5Fj+EDe8gO/lxc1BzfMpxvA=="],