feat: TypeScript telemetry client SDK v0.1.0

Standalone npm package (@mosaicstack/telemetry-client) for reporting
task-completion telemetry and querying predictions from the Mosaic
Stack Telemetry server.

- TelemetryClient with setInterval-based background flush
- EventQueue (bounded FIFO array)
- BatchSubmitter with native fetch, exponential backoff, Retry-After
- PredictionCache (Map + TTL)
- EventBuilder with auto-generated event_id/timestamp
- Zero runtime dependencies (Node 18+ native APIs)
- 43 tests, 86% branch coverage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/config.ts

@@ -0,0 +1,62 @@
+export interface TelemetryConfig {
+  /** Base URL of the telemetry server (e.g., "https://tel.mosaicstack.dev") */
+  serverUrl: string;
+  /** API key for authentication (64-char hex string) */
+  apiKey: string;
+  /** Instance UUID for this client */
+  instanceId: string;
+  /** Whether telemetry collection is enabled. Default: true */
+  enabled?: boolean;
+  /** Interval between automatic batch submissions in ms. Default: 300_000 (5 min) */
+  submitIntervalMs?: number;
+  /** Maximum number of events held in queue. Default: 1000 */
+  maxQueueSize?: number;
+  /** Maximum events per batch submission. Default: 100 */
+  batchSize?: number;
+  /** HTTP request timeout in ms. Default: 10_000 */
+  requestTimeoutMs?: number;
+  /** TTL for cached predictions in ms. Default: 21_600_000 (6 hours) */
+  predictionCacheTtlMs?: number;
+  /** If true, log events instead of sending them. Default: false */
+  dryRun?: boolean;
+  /** Maximum number of retries on failure. Default: 3 */
+  maxRetries?: number;
+  /** Optional callback invoked on errors */
+  onError?: (error: Error) => void;
+}
+
+export interface ResolvedConfig {
+  serverUrl: string;
+  apiKey: string;
+  instanceId: string;
+  enabled: boolean;
+  submitIntervalMs: number;
+  maxQueueSize: number;
+  batchSize: number;
+  requestTimeoutMs: number;
+  predictionCacheTtlMs: number;
+  dryRun: boolean;
+  maxRetries: number;
+  onError: (error: Error) => void;
+}
+
+const DEFAULT_ON_ERROR = (_error: Error): void => {
+  // Silent by default
+};
+
+export function resolveConfig(config: TelemetryConfig): ResolvedConfig {
+  return {
+    serverUrl: config.serverUrl.replace(/\/+$/, ''),
+    apiKey: config.apiKey,
+    instanceId: config.instanceId,
+    enabled: config.enabled ?? true,
+    submitIntervalMs: config.submitIntervalMs ?? 300_000,
+    maxQueueSize: config.maxQueueSize ?? 1000,
+    batchSize: config.batchSize ?? 100,
+    requestTimeoutMs: config.requestTimeoutMs ?? 10_000,
+    predictionCacheTtlMs: config.predictionCacheTtlMs ?? 21_600_000,
+    dryRun: config.dryRun ?? false,
+    maxRetries: config.maxRetries ?? 3,
+    onError: config.onError ?? DEFAULT_ON_ERROR,
+  };
+}