Setup Analytics & Error Tracking

[HarshCasper]

Summary

• Add shared PostHog telemetry across all MCP tools
• Add telemetry opt-out flags and privacy-safe sanitization
• Standardize success/error events with shared event_id
• Switch to batched sending with bounded shutdown flush
• Add allowlist coverage test and update README telemetry docs

Output

[remotesynth]

I've verified that the build runs and loads properly.