[$25 BOUNTY] [TypeScript] Add reconnect metrics for frontend sockets

[Saiaaax]

Summary

Adds a ReconnectMetrics class that tracks WebSocket reconnect attempts, successes, failures, consecutive failures, and backoff delay statistics for frontend sockets.

Closes #73

Changes

• New: frontend/src/services/reconnectMetrics.ts — ReconnectMetrics class with:

  • recordAttempt(backoffMs) — track a reconnect attempt with its backoff delay
  • recordSuccess(backoffMs) — track a successful reconnect
  • recordFailure() — track a failed reconnect (gave up)
  • snapshot() — return current metrics as a plain object
  • reset() — clear all counters
  • Tracks: total attempts, successes, failures, consecutive failures, min/max/avg backoff, timestamps

• New: frontend/src/services/reconnectMetrics.test.ts — 8 unit tests:

  • Starts with zero counts
  • Records attempts with backoff delay
  • Records successful reconnects
  • Records failures and consecutive failures
  • Resets consecutive failures on success
  • Tracks backoff statistics (min, max, average)
  • Handles zero backoff (initial attempt)
  • Resets all counters
  • Validates lastAttemptAt timestamp

• Updated: docs/OPERATIONS.md — Added "Frontend WebSocket Reconnect Metrics" section

Testing

cd frontend && npm test -- --run reconnectMetrics

Checklist

• Relevant modules affected by these changes build locally
• Tests pass locally
• Diagnostic build log is committed in this PR
• Documentation has been updated, if applicable
• Configuration or schema changes are documented, if applicable
• No generated build artifacts are committed, except the required diagnostic build log
• Changes are scoped to the PR purpose and avoid unrelated cleanup
• Security, privacy, and error-handling implications have been considered

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• I would like to request that my diagnostic build log is removed before merging

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Payout address: 0x5253757322092903C2F0a8EfEed592344216CC7E
Diagnostic artifact reference: diagnostic/build-bd0b6e82.logd