Make the dashboard handle structured log lines (#24131)

The dashboard version of get-convex/convex#24129.

Note that we still allow unstructured log lines too. There should be no user visible changes here.

GitOrigin-RevId: 731248c2c930d35b641f209b07dd21d808513578

Author: sshader

Diff for: npm-packages/system-udfs/convex/_system/frontend/common.ts

@@ -17,12 +17,22 @@ export type UdfWrite = {
   source: string;
 };
 
+export type LogLevel = "LOG" | "DEBUG" | "INFO" | "WARN" | "ERROR";
+
+export type StructuredLogLine = {
+  messages: string[];
+  level: LogLevel;
+  timestamp: number;
+  isTruncated: boolean;
+};
+export type LogLine = string | StructuredLogLine;
+
 export type FunctionExecutionCompletion = {
   kind: "Completion";
   identifier: string;
   udfType: UdfType;
   arguments: string[];
-  logLines: string[];
+  logLines: LogLine[];
   // Unix timestamp (in seconds)
   timestamp: number;
 
@@ -47,7 +57,7 @@ export type FunctionExecutionProgess = {
   udfType: UdfType;
   // Unix timestamp (in seconds)
   timestamp: number;
-  logLines: string[];
+  logLines: LogLine[];
   requestId: string;
   executionId: string;
 };