Enhance environment variable parsing and account snapshot validation

- Introduced `normalizeEnvValue` function to improve handling of environment variable values, including trimming, unquoting, and stripping inline comments.
- Updated `resolveSymbolFromEnv` and parsing functions to utilize the new normalization logic.
- Added `validateAccountSnapshotForSymbol` function to validate account snapshots, ensuring numeric fields are correctly formatted and flagging any issues.
- Implemented tests for environment variable parsing and account snapshot validation to ensure robustness and correctness.

tests/standx-rest-health.test.ts

@@ -0,0 +1,55 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { StandxGateway } from "../src/exchanges/standx/gateway";
+
+const ORIGINAL_FETCH = globalThis.fetch;
+
+afterEach(() => {
+  globalThis.fetch = ORIGINAL_FETCH;
+  vi.restoreAllMocks();
+});
+
+describe("StandxGateway REST health", () => {
+  it("emits unhealthy after 3 consecutive REST failures, then healthy after a success", async () => {
+    const gateway = new StandxGateway({
+      token: "test-token",
+      symbol: "BTC-USD",
+      baseUrl: "https://example.com",
+      wsUrl: "wss://example.com/ws",
+      logger: () => {},
+    });
+
+    const events: Array<{ state: string; consecutiveErrors: number }> = [];
+    gateway.onRestHealthEvent((state, info) => {
+      events.push({ state, consecutiveErrors: info.consecutiveErrors });
+    });
+
+    globalThis.fetch = vi.fn(async () => {
+      return {
+        ok: false,
+        status: 500,
+        text: async () => "server error",
+      } as any;
+    }) as any;
+
+    await expect(gateway.queryOpenOrders("BTC-USD")).rejects.toThrow();
+    await expect(gateway.queryOpenOrders("BTC-USD")).rejects.toThrow();
+    await expect(gateway.queryOpenOrders("BTC-USD")).rejects.toThrow();
+
+    expect(events).toEqual([{ state: "unhealthy", consecutiveErrors: 3 }]);
+
+    globalThis.fetch = vi.fn(async () => {
+      return {
+        ok: true,
+        status: 200,
+        text: async () => "[]",
+      } as any;
+    }) as any;
+
+    await expect(gateway.queryOpenOrders("BTC-USD")).resolves.toEqual([]);
+    expect(events).toEqual([
+      { state: "unhealthy", consecutiveErrors: 3 },
+      { state: "healthy", consecutiveErrors: 0 },
+    ]);
+  });
+});
+