feat: Reinitialize frontend with SvelteKit and TypeScript

- Delete old Vite+Svelte frontend
- Initialize new SvelteKit project with TypeScript
- Configure Tailwind CSS v4 + DaisyUI
- Implement JWT authentication with auto-refresh
- Create login page with form validation (Zod)
- Add protected route guards
- Update Docker configuration for single-stage build
- Add E2E tests with Playwright (6/11 passing)
- Fix Svelte 5 reactivity with $state() runes

Known issues:
- 5 E2E tests failing (timing/async issues)
- Token refresh implementation needs debugging
- Validation error display timing

frontend/node_modules/zod-v3-to-json-schema/dist/cjs/parsers/nullable.js

@@ -0,0 +1,37 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.parseNullableDef = void 0;
+const parseDef_js_1 = require("../parseDef.js");
+const union_js_1 = require("./union.js");
+function parseNullableDef(def, refs) {
+    if (["ZodString", "ZodNumber", "ZodBigInt", "ZodBoolean", "ZodNull"].includes(def.innerType._def.typeName) &&
+        (!def.innerType._def.checks || !def.innerType._def.checks.length)) {
+        if (refs.target === "openApi3") {
+            return {
+                type: union_js_1.primitiveMappings[def.innerType._def.typeName],
+                nullable: true,
+            };
+        }
+        return {
+            type: [
+                union_js_1.primitiveMappings[def.innerType._def.typeName],
+                "null",
+            ],
+        };
+    }
+    if (refs.target === "openApi3") {
+        const base = (0, parseDef_js_1.parseDef)(def.innerType._def, {
+            ...refs,
+            currentPath: [...refs.currentPath],
+        });
+        if (base && "$ref" in base)
+            return { allOf: [base], nullable: true };
+        return base && { ...base, nullable: true };
+    }
+    const base = (0, parseDef_js_1.parseDef)(def.innerType._def, {
+        ...refs,
+        currentPath: [...refs.currentPath, "anyOf", "0"],
+    });
+    return base && { anyOf: [base, { type: "null" }] };
+}
+exports.parseNullableDef = parseNullableDef;