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>

.gitignore

@@ -0,0 +1,5 @@
+node_modules/
+dist/
+coverage/
+*.tsbuildinfo
+.env