Add 'award' telemetry event type for arbitrary score grants

Summary

Add a new award event type to the telemetry pipeline, separate from cli_invocation, that allows granting arbitrary scores to users. This enables rewarding contributions that aren't captured by CLI usage — e.g., community participation, bug reports, content creation, event attendance.

Motivation

Today, scoring is driven entirely by cli_invocation events processed through the activity scoring algorithm (group-capped base points + diversity bonus × streak × rolling activity multiplier). There's no way to credit users for contributions outside of CLI usage without hacking synthetic cli_invocation events.

An award event would be a first-class mechanism for granting points that bypass the activity scoring formula and add directly to a user's total score.

Design sketch

• Event shape: { event: "award", distinct_id: "...", properties: { username, points, reason, grantedBy? } }
• Telemetry pipeline: StatsConsumer recognizes award events, accumulates them in a new field on username_metrics (e.g., awardPoints)
• Queue entry: metricsSnapshots includes award points alongside eventCounts/activeDates/totalEvents
• Scoring: processScoreBatch adds award points directly to the user's total score as a separate contribution (not run through the activity scoring algorithm)
• Idempotency: Each award event should have a unique key (e.g., reason + timestamp) to prevent double-counting on reprocessing

Open questions

• Should awards be capped or unbounded?
• Admin-only ingestion or also via API keys?
• Should award history be visible on the user's profile?
• Should awards trigger tier badge claims (they already would via processScoreBatch)?