feat: profile and time deploy operations and facts

[wowi42]

Summary

Adds per-host timing for the prepare and execute phases of every operation, plus per-host per-fact timing. Surfaces the data via two new flags and always prints total elapsed wall time at the end of a run.

• --timings: human-readable summary of the slowest operations and facts at the end of the run
• --timings-json: structured timing data emitted to stdout for external tooling
• --log-timestamps (also PYINFRA_LOG_TIMESTAMPS=1): wall-clock prefix on every log line

Closes #1717. Supersedes #469 and #640.

Implementation notes

• New StateTimings dataclass on State.timings accumulates timings as the deploy progresses. Per-host data is stored under the concrete Host, with a small helper resolving gevent context proxies before storing them as dict keys.
• Operations measure two phases: prepare time (the change-detection iteration of command_generator()) and execute time (the retry loop in _run_host_op).
• Facts measure the entire _get_fact body so the network call and process() parsing are both included. Multiple samples per fact key are kept since facts can be re-fetched.
• Default behaviour is unchanged unless a user passes one of the new flags. The total elapsed line is always printed (cheap, useful) but no slowest-ops table is shown without --timings.

Example

 pyinfra inventory.py test_unarchive.py --timings -y
--> Loading config...
--> Loading inventory...
--> Connecting to hosts...
    [10.0.10.23] Connected
    [10.0.10.21] Connected
    [10.0.10.22] Connected
    [10.0.10.20] Connected

--> Preparing operation files...
    Loading: test_unarchive.py
    [10.0.10.20] Ready: test_unarchive.py
    [10.0.10.22] Ready: test_unarchive.py
    [10.0.10.21] Ready: test_unarchive.py
    [10.0.10.23] Ready: test_unarchive.py

--> Skipping change detection
--> Beginning operation run...
--> Starting operation: Clean previous extraction roots
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Starting operation: Upload and extract tar.gz
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Starting operation: Extract with creates marker
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Starting operation: Re-extract should skip (creates exists)
    [10.0.10.20] No changes
    [10.0.10.21] No changes
    [10.0.10.23] No changes
    [10.0.10.22] No changes

--> Starting operation: Extract with extra_opts (verbose)
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Starting operation: Extract and chown tree
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Starting operation: Verify extracted payloads
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Starting operation: Verify chown applied
    [10.0.10.20] Success
    [10.0.10.23] Success
    [10.0.10.21] Success
    [10.0.10.22] Success

--> Starting operation: Tear down extraction roots
    [10.0.10.20] Success
    [10.0.10.21] Success
    [10.0.10.23] Success
    [10.0.10.22] Success

--> Results:
    Operation                                 Hosts   Success   Error   No Change
    Clean previous extraction roots           4       4         -       -
    Upload and extract tar.gz                 4       4         -       -
    Extract with creates marker               4       4         -       -
    Re-extract should skip (creates exists)   4       -         -       4
    Extract with extra_opts (verbose)         4       4         -       -
    Extract and chown tree                    4       4         -       -
    Verify extracted payloads                 4       4         -       -
    Verify chown applied                      4       4         -       -
    Tear down extraction roots                4       4         -       -
    Grand total                               36      32        -       4

--> Finished, took 2.49s

--> Timings:
    Operation                                 Hosts   Prepare (sum)   Execute (sum)   Slowest host
    Extract and chown tree                    4       0ms             1.07s           474ms
    Upload and extract tar.gz                 4       0ms             915ms           347ms
    Tear down extraction roots                4       0ms             852ms           361ms
    Verify extracted payloads                 4       0ms             839ms           358ms
    Extract with creates marker               4       0ms             760ms           251ms
    Clean previous extraction roots           4       0ms             754ms           223ms
    Extract with extra_opts (verbose)         4       0ms             617ms           262ms
    Verify chown applied                      4       0ms             138ms           103ms
    Re-extract should skip (creates exists)   4       0ms             137ms           100ms

    Fact                                                  Hosts   Calls   Total   Slowest
    files.Directory (path=/tmp)                           4       16      635ms   122ms
    server.Which (command=tar)                            4       4       481ms   239ms
    files.File (path=/etc/passwd)                         4       8       395ms   63ms
    server.TmpDir                                         4       4       246ms   96ms
    files.File (path=/tmp/unarchive-creates/marker.txt)   4       8       217ms   100ms

--> Disconnecting from hosts...

Test plan

• scripts/dev-lint.sh (ruff, ruff format, mypy, arguments sync) passes
• scripts/dev-test.sh passes (1675 tests)
• New unit tests cover StateTimings accumulators, end-to-end op timing population, and JSON output shape
• Manual smoke test against a real host (pyinfra @local exec -- echo hi --timings, --timings-json, --log-timestamps)