Emit HTTP cache hit/miss as metrics instead of logs

[arreyder]

Summary

• Replace spammy debug log statements for HTTP cache hits/misses with OpenTelemetry metrics
• Add WithMetricsHandler option to BaseHttpClient to enable metric recording
• New metrics: baton_sdk.http_cache_hit and baton_sdk.http_cache_miss

Test plan

• Existing tests pass
• Verify metrics are emitted when a metrics handler is configured
• Verify backward compatibility (no metrics handler = no-op)

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Implemented metrics collection for HTTP cache events, automatically tracking cache hits and misses during operations.
  • Added optional metrics handler configuration to HTTP client, enabling monitoring of cache performance and optimization opportunities.
  • Cache metrics now available for integration with monitoring and observability systems.

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[coderabbitai]

Walkthrough

The PR introduces metrics integration for HTTP cache events in the HTTP client wrapper. A metrics handler option is added to configure metrics collection, with helper methods to emit cache hit and miss metrics during cache operations.

Changes

Cohort / File(s)	Summary
Metrics Integration for HTTP Caching pkg/uhttp/wrapper.go	Added WithMetricsHandler() option method and metricsHandler field to BaseHttpClient. Introduced recordCacheHit() and recordCacheMiss() helpers. Cache operations now emit metrics (hit/miss counters) when a metrics handler is configured. Replaces prior debug logging with metric increments.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐰 Hop! Hop! The metrics flow,
Cache hits now aglow!
Handler hooks collect the tale,
Of every cache hit and miss without fail!
Instrumented and true, observability rules! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 66.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Emit HTTP cache hit/miss as metrics instead of logs' accurately describes the main change: replacing debug logging of HTTP cache events with OpenTelemetry metrics emission.

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✨ Finishing touches

• 📝 Generate docstrings

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[ggreer]

Would it make more sense to put the metrics handler on the cache itself?