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>

vitest.config.ts

@@ -0,0 +1,19 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    globals: true,
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'text-summary'],
+      include: ['src/**/*.ts'],
+      exclude: ['src/types/**'],
+      thresholds: {
+        statements: 85,
+        branches: 85,
+        functions: 85,
+        lines: 85,
+      },
+    },
+  },
+});