refactor(Font/model): move baseFontStore and unifiedFontStore to subdirectories, rename errors/index to errors/errors

src/entities/Font/lib/errors/errors.ts

@@ -0,0 +1,28 @@
+/**
+ * Thrown when the network request to the proxy API fails.
+ * Wraps the underlying fetch error (timeout, DNS failure, connection refused, etc.).
+ */
+export class FontNetworkError extends Error {
+    readonly name = 'FontNetworkError';
+
+    constructor(public readonly cause?: unknown) {
+        super('Failed to fetch fonts from proxy API');
+    }
+}
+
+/**
+ * Thrown when the proxy API returns a response with an unexpected shape.
+ *
+ * @property field - The name of the field that failed validation (e.g. `'response'`, `'response.fonts'`).
+ * @property received - The actual value received at that field, for debugging.
+ */
+export class FontResponseError extends Error {
+    readonly name = 'FontResponseError';
+
+    constructor(
+        public readonly field: string,
+        public readonly received: unknown,
+    ) {
+        super(`Invalid proxy API response: ${field}`);
+    }
+}