refactor(telemetry): OTel-Traces shape and error isolation

- Phase events compose hierarchical eventNames; new parentEventId
  encodes parent/child unambiguously under retries. time also carries
  a traceId so every timed event maps to an OTel span.
- Trace -> Span; phase callback receives a child Span, so grandchildren
  are just recursion. time/trace/phase accept caller measurements.
- All emission routed through #safeEmit so telemetry failures never
  reach callers; per-sink try/catch isolates writes.
- Address review fixes: logger.dispose last, readonly fields, isTelemetryLevel
  guard, platformType -> platformName, telemetry tag on the setting,
  setDeploymentUrl test assertions, reactive-level test fix.

Author: EhabY

package.json

@@ -201,7 +201,10 @@
 						"Disable telemetry collection.",
 						"Record events on this machine only."
 					],
-					"default": "local"
+					"default": "local",
+					"tags": [
+						"telemetry"
+					]
 				}
 			}
 		},

src/core/container.ts

@@ -135,9 +135,10 @@ export class ServiceContainer implements vscode.Disposable {
 	 */
 	dispose(): void {
 		this.contextManager.dispose();
-		this.logger.dispose();
 		this.loginCoordinator.dispose();
 		// Fire-and-forget: VS Code does not await deactivation.
 		void this.telemetryService.dispose();
+		// Logger last so telemetry teardown can still log warnings.
+		this.logger.dispose();
 	}
 }

src/telemetry/emit.ts

@@ -6,41 +6,45 @@ import { toError } from "../error/errorUtils";
 /** Telemetry level, mirrors `coder.telemetry.level`. Ordered: off < local. */
 export type TelemetryLevel = "off" | "local";
 
-/** Session-stable resource attributes. Field names follow OTel conventions. */
+/** Session-stable resource attributes. Field names are inspired by OTel
+ * resource attributes; they are camelCase TypeScript and not a 1:1 mapping. */
 export interface SessionContext {
 	readonly extensionVersion: string;
 	readonly machineId: string;
 	readonly sessionId: string;
 	readonly osType: string;
 	readonly osVersion: string;
 	readonly hostArch: string;
-	readonly platformType: string;
+	readonly platformName: string;
 	readonly platformVersion: string;
 }
 
 /** Per-event context: session attributes plus the current deployment URL. */
 export interface TelemetryContext extends SessionContext {
-	deploymentUrl: string;
+	readonly deploymentUrl: string;
 }
 
 export interface TelemetryEvent {
-	eventId: string;
-	eventName: string;
-	timestamp: string;
-	eventSequence: number;
+	readonly eventId: string;
+	readonly eventName: string;
+	readonly timestamp: string;
+	readonly eventSequence: number;
 
-	context: TelemetryContext;
+	readonly context: TelemetryContext;
 
-	properties: Record<string, string>;
-	measurements: Record<string, number>;
+	readonly properties: Readonly<Record<string, string>>;
+	readonly measurements: Readonly<Record<string, number>>;
 
-	traceId?: string;
+	/** Shared by all events in a trace. Maps to OTel `trace_id`. */
+	readonly traceId?: string;
+	/** Set on phase children only. Equals the parent event's `eventId`. Maps to OTel `parent_span_id`. */
+	readonly parentEventId?: string;
 
-	error?: {
+	readonly error?: Readonly<{
 		message: string;
 		type?: string;
 		code?: string;
-	};
+	}>;
 }
 
 /**
@@ -70,7 +74,7 @@ export function buildSession(ctx: vscode.ExtensionContext): SessionContext {
 		osType: detectOsType(),
 		osVersion: os.release(),
 		hostArch: process.arch,
-		platformType: vscode.env.appName,
+		platformName: vscode.env.appName,
 		platformVersion: vscode.version,
 	};
 }
@@ -80,15 +84,13 @@ export function buildErrorBlock(
 	value: unknown,
 ): NonNullable<TelemetryEvent["error"]> {
 	const err = toError(value);
-	const block: NonNullable<TelemetryEvent["error"]> = { message: err.message };
-	if (err.name && err.name !== "Error") {
-		block.type = err.name;
-	}
 	const rawCode = (value as { code?: unknown } | null | undefined)?.code;
-	if (typeof rawCode === "string" || typeof rawCode === "number") {
-		block.code = String(rawCode);
-	}
-	return block;
+	const hasCode = typeof rawCode === "string" || typeof rawCode === "number";
+	return {
+		message: err.message,
+		...(err.name && err.name !== "Error" && { type: err.name }),
+		...(hasCode && { code: String(rawCode) }),
+	};
 }
 
 // Node uses "win32" on Windows; OTel's os.type is "windows".