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.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);
     },
   };
 }