EPIC: Improve PR Workflow Performance

[josecelano]

Goal

Reduce the execution time of the critical PR validation workflows while preserving verification quality.

Why

Current PR checks are a bottleneck for merge throughput:

• container workflow: 34m 57s
• testing workflow: 40m 44s

Slow feedback encourages batching unrelated changes and increases regression risk. This is especially important with increased AI-assisted change volume.

Scope

• Baseline profiling (cold/warm cache, bottleneck identification)
• Prioritized workflow optimizations driven by measured impact
• Keep quality gates intact
• Optimize for end-to-end PR wait time until all required checks complete

Initial subissues planned

• Baseline workflow profiling and bottleneck analysis
• Narrow Containerfile build targets to tracker image needs
• Evaluate test execution policy in container image build
• Improve dependency-layer cache reuse within each workflow
• Evaluate removing duplicate container build from container workflow
• Include existing issue Research: Reduce Build Times with sccache #1726 as child issue after EPIC creation

Spec

• docs/issues/drafts/workflow-performance-epic.md

This EPIC uses iterative, evidence-driven prioritization after baseline data is available.