Improve cli output in an interactive terminal

[GuillaumeLagrange]

Summary

Improve the CLI output in interactive terminal (local mode) with richer visual hierarchy, rolling log buffer, and polished feedback.

Visual polish

• Style the ASCII banner with CodSpeed orange
• Richer local logger: styled group headers, spinner with elapsed time, colored log levels (error/warn/debug), completion checkmarks
• Color-coded benchmark result tables: icons per instrument type, cyan primary metrics, StdDev color thresholds
• Impact reporting: directional arrows with color, cleaner report URL display

Rolling buffer for executor output

• Add a rolling buffer that shows the last N lines of executor stdout/stderr instead of spamming the full output
• Add --show-full-output flag to bypass the rolling buffer when needed

Refactors

• Flatten orchestrator execution loop over (command, mode) pairs — fixes a bug where single-mode + multiple entrypoint targets would reuse the same profile folder
• Move EXEC_HARNESS_VERSION and EXEC_HARNESS_COMMAND to orchestrator mod
• Remove the closure argument to poll in favor of polling options
• Add a standalone spinner while waiting for poll results

recording-20260313-170535.mp4

[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks

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_{Comparing cod-2210-improve-exec-harnessscli-stdoutstderr-output-in-local-mode (dd45aec) with main (ce1ad6e)}