feat: add workflow telemetry traces (#995)

Instrument the main user workflows with telemetry spans, following
OpenTelemetry conventions for span outcomes.

- Trace workspace open (sidebar / URI / command) and the workspace picker,
  recording workspace and agent context without identifying names.
- Trace diagnostic commands (speed test, support bundle, telemetry export)
  and workspace start / update prompts.
- Add per-workflow instrumentation modules (workspaceOpen, diagnostics) over
  shared outcome helpers; callers declare telemetry dimensions explicitly
  (e.g. open `source`) rather than inferring them from arguments.
- Map outcomes to OTel: success / aborted / error span results, `error.type`
  on errors, and UNSET status for intentional cancellation.

Closes #986

Author: EhabY

src/api/authInterceptor.ts

@@ -95,7 +95,7 @@ export class AuthInterceptor implements vscode.Disposable {
 		}
 
 		this.logger.debug("Received 401 response, attempting recovery");
-		return this.authTelemetry.traceAuthRecovery(async (recorder) => {
+		return this.authTelemetry.traceRecovery(async (recorder) => {
 			recorder.logReceived();
 
 			// 1) OAuth refresh path.