Feat: add the exec subcommand to run an arbitrary rust binary

[GuillaumeLagrange]

• Depends on the monorepo pr for the new endpoint
• Refactor to move out of the run module the whole executor logic
• Create a new ExecutionContext that holds all the data required by the executor and other parts to work
• Factorize the logic between exec and run while keeping some stuff modular
• Parse the perf map during wt teardown if not outputing pipedata
  • This is temporary, while the upstream linux-perf-data cannot parse the pipedata format, ideally we remove the /proc/<pid>/maps parsing logic altogether

Some of the logic would still need to be refactored to be perfectly clean, but the PR is starting to be quite huge already

CI fails because of unrelated version mismatch within the repo (the plan job), should not affect review

[not-matthias]

Look good! I like the new structure 👍

[Copilot]

Pull request overview

This PR introduces a new exec subcommand to run arbitrary Rust binaries with CodSpeed instrumentation, and performs a substantial refactoring to support this feature. The changes separate executor logic from the run module, introduce a unified ExecutionContext, and modify perf handling to support both streaming (pipedata) and file-based (perf.data) formats.

Key Changes:

• Added exec subcommand with corresponding harness binary for wrapping commands
• Refactored executor logic from run::runner to dedicated executor module
• Created ExecutionContext to consolidate execution state (config, system info, provider, logger)
• Modified perf handling to conditionally output .pipedata (streaming) vs .perf.data (file-based) format
• Moved run_environment and instruments modules to top-level

Reviewed changes

Copilot reviewed 118 out of 150 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/executor/mod.rs	Core executor module with shared execution logic
src/executor/execution_context.rs	New ExecutionContext for consolidating execution state
src/executor/config.rs	Moved and refactored Config from run module
src/exec/mod.rs	New exec subcommand implementation
src/run/mod.rs	Refactored to use new executor infrastructure
src/run_environment/*	Moved from run::run_environment to top level
src/executor/wall_time/perf/*	Perf handling with pipedata vs file-based modes
crates/exec-harness/*	New harness binary for wrapping arbitrary commands
src/app.rs	Added exec subcommand to CLI
Various test files	Updated to work with new ExecutionContext pattern

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[not-matthias]

Looks good overall, it's mostly just about how we can reduce duplication while also keeping clarity. Feel free to challenge any comment, I'll let you decide where it does and doesn't make sense.

[adriencaccia]

LGTM, but as you said the refactor is not complete, there are still a lot of stuff defined in run that is being used in other modules at the same level.
Let's make sure you have an issue for this, which describe the idea state we want this repo to end up in