Feature/issue 47 ingestion api

[Khantdotcom]

@joeldickson
feat: add /command telemetry, sessionId, and rspack support (#47)

Extends the ingestion API to capture the full local dev lifecycle,
accommodating the new multi-phase telemetry generated by devfeedback-js.

Key changes:

• Add POST /command endpoint for full lifecycle events (install,
  devserver, clientready) with non-blocking background queueing.
• Add POST /rspack endpoint (accepting both rspack and rsbuild),
  while keeping backward compatibility on /webpack for legacy clients.
• Add indexed sessionId (uuid) across all telemetry endpoints (webpack,
  vite, command) to allow stitching spans from install to clientready.
• Create CommandEvent table and a CommandEventNpmTimer child table
  (Option 2) to track and aggregate expensive npm install phases org-wide.
• Make spooledAt a first-class nullable column to accurately reflect
  delayed event delivery without conflating with ingestion time.
• Update prebundled to a nullable boolean to properly handle its
  tri-state nature (true, false, absent) for Vite/Rolldown.
• Generate AddCommandEventsAndSessionId EF Core migration.
• Add comprehensive integration tests ensuring additive-tolerance
  and backward compatibility for older CLI clients.

Resolves #47
Companion to agoda-com/devfeedback-js#46

[Khantdotcom]

@joeldickson Can you review this PR please? Thank you!