fix(FN-2371): preserve log severity in dashboard TUI capture

- Add severity control markers to core and engine structured loggers while keeping info logs on stderr transport
- Parse and strip internal severity markers in dashboard TUI console capture so logger.log entries render with info icons instead of error icons
- Expand dashboard TUI tests to cover captured console severity mapping and structured logger behavior, plus logger unit tests in core/engine
- Add a patch changeset for @runfusion/fusion describing the TUI log severity icon fix

packages/core/src/logger.test.ts

@@ -0,0 +1,43 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { createLogger } from "./logger.js";
+
+describe("core createLogger", () => {
+  let logSpy: ReturnType<typeof vi.spyOn>;
+  let warnSpy: ReturnType<typeof vi.spyOn>;
+  let errorSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    logSpy = vi.spyOn(console, "log").mockImplementation(() => {});
+    warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+    errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    logSpy.mockRestore();
+    warnSpy.mockRestore();
+    errorSpy.mockRestore();
+  });
+
+  it("emits info logs to stderr with an info severity marker", () => {
+    const logger = createLogger("core-test");
+    logger.log("hello");
+
+    expect(logSpy).not.toHaveBeenCalled();
+    expect(errorSpy).toHaveBeenCalledWith("\u0000fnlvl=info\u0000[core-test] hello");
+  });
+
+  it("emits warn logs with a warn severity marker", () => {
+    const logger = createLogger("core-test");
+    logger.warn("careful");
+
+    expect(warnSpy).toHaveBeenCalledWith("\u0000fnlvl=warn\u0000[core-test] careful");
+  });
+
+  it("emits error logs with an error severity marker", () => {
+    const logger = createLogger("core-test");
+    const err = new Error("boom");
+    logger.error("broken", err);
+
+    expect(errorSpy).toHaveBeenCalledWith("\u0000fnlvl=error\u0000[core-test] broken", err);
+  });
+});

packages/core/src/logger.ts

@@ -20,6 +20,13 @@ export interface Logger {
   error(message: string, ...args: unknown[]): void;
 }
 
+const LOG_LEVEL_MARKER_PREFIX = "\u0000fnlvl=";
+const LOG_LEVEL_MARKER_SUFFIX = "\u0000";
+
+function withSeverityMarker(level: "info" | "warn" | "error", payload: string): string {
+  return `${LOG_LEVEL_MARKER_PREFIX}${level}${LOG_LEVEL_MARKER_SUFFIX}${payload}`;
+}
+
 /**
  * Create a structured logger that prefixes every message with `[prefix]`.
  *
@@ -27,18 +34,22 @@ export interface Logger {
  * @returns A `Logger` whose output is prefixed and sent to stderr for normal
  *          logs and errors. Keeping logs off stdout prevents command/test
  *          output consumers from receiving Fusion execution chatter.
+ *
+ *          The logger prepends an internal control-character severity marker
+ *          so dashboard TUI console-capture can preserve info/warn/error
+ *          semantics even when `log()` is transported via `console.error`.
  */
 export function createLogger(prefix: string): Logger {
   const tag = `[${prefix}]`;
   return {
     log(message: string, ...args: unknown[]) {
-      console.error(`${tag} ${message}`, ...args);
+      console.error(withSeverityMarker("info", `${tag} ${message}`), ...args);
     },
     warn(message: string, ...args: unknown[]) {
-      console.warn(`${tag} ${message}`, ...args);
+      console.warn(withSeverityMarker("warn", `${tag} ${message}`), ...args);
     },
     error(message: string, ...args: unknown[]) {
-      console.error(`${tag} ${message}`, ...args);
+      console.error(withSeverityMarker("error", `${tag} ${message}`), ...args);
     },
   };
 }