Inject Clock and metrics::Recorder into acquire_with_octocrab_installation

[coderabbitai]

Summary

Introduce a Clock seam into acquire_with_octocrab_installation (in src/github/installation_token.rs) so that token acquisition timing is deterministically testable without mocking wall-clock time, and thread an explicit metrics::Recorder reference through the acquisition path to eliminate implicit global-state side effects.

Motivation

src/github/installation_token.rs currently calls Instant::now() and SystemTime::now() directly, and emits metrics via the implicit global metrics recorder. This means:

1. Non-deterministic timing — tests cannot control the elapsed duration reported in latency histograms or log fields, so assertions on timing values are inherently flaky or must be left out.
2. Implicit global-state mutation — metrics::counter! and metrics::histogram! write to whatever recorder happens to be installed globally at the time. This makes isolated unit tests harder and can cause interference between parallel test threads.

Acceptance criteria

• Define or reuse a Clock trait (e.g. mockable::Clock or an equivalent in this crate) with at minimum a now() -> Instant (or equivalent) method.
• Inject an &impl Clock parameter into acquire_with_octocrab_installation (and any private helpers that call Instant::now() / SystemTime::now()).
• Inject an explicit &dyn metrics::Recorder (or &impl metrics::Recorder) parameter so tests can pass RecordingMetrics without installing a global recorder.
• Provide a SystemClock (production) and a FixedClock (test) implementation.
• Add deterministic unit tests for the latency histogram and timeout-failure counter using FixedClock and RecordingMetrics.
• Remove or replace direct calls to Instant::now() and SystemTime::now() within the acquisition path.

References

• Raised in PR Add cargo audit dependency gate #100 (comment): Add cargo audit dependency gate #100
• Related: src/github/installation_token.rs, src/github/test_support.rs

[coderabbitai]

🔗 Related PRs

leynos/frankie#65 - Extract time-travel orchestration into a pure library service (2.2.7) [merged]
#78 - Plan and implement library-owned Run subcommand (6.1.1) [merged]
leynos/axinite#175 - Flatten build tool override resolution (#39) [merged]
leynos/actix-v2a#30 - Update documentation after the SSE module lands (1.2.2) [merged]
leynos/mdtablefix#303 - Add observability for inline wrapping token classification (#296) [merged]

---

📝 Issue Planner

_{Check the box below or use the @coderabbitai plan command to generate an implementation plan and prompts that you can use with your favorite coding assistant.}

• Create Plan

---

🧪 Issue enrichment is currently in open beta.

You can configure auto-planning by selecting labels in the issue_enrichment configuration.

To disable automatic issue enrichment, add the following to your .coderabbit.yaml:

issue_enrichment:
  auto_enrich:
    enabled: false

💬 Have feedback or questions? Drop into our discord!