feat(cli): add toolr project venv run

[s0undt3ch]

Summary

Adds toolr project venv run [--no-sync] [--quiet] -- <CMD> [ARGS...] — a first-class way to run any command inside the project's managed tools venv. Resolves #373.

The one-liner for running a command-package's tests becomes:

toolr project venv run -- pytest tools/

Rather than the issue's pytest-specific toolr test, this is a general runner: test is just one call of it, CI uses it verbatim, and there's zero runner lock-in because there is no runner concept. It lives under the reserved project venv group (never toolr run, which would collide with user-defined commands).

Behavior

• Default: freshness-gated auto-sync (via ensure_venv_ready, exactly like venv shell and uv run), then runs the command with $VIRTUAL_ENV/$TOOLR_VENV/$PATH set so entry points resolve from the venv. Self-healing past the mtime freshness heuristic.
• --no-sync: pure, uv-free path for deterministic CI — never touches the venv, errors fatally if it is missing or stale.
• No command echo on the happy path (parity with uv run/poetry run/cargo run); child owns stdout/stderr; exit code passes straight through; caller's cwd preserved.
• Command-not-found gives an actionable nudge (exit 127) for argv[0]; python -m missingmodule errors pass through untouched.
• --quiet forwards to the auto-sync step only; --quiet only, no short -q.

Discoverability

project init next-steps and venv sync success output now advertise the one-liner.

Docs & skills

• New docs/cli.md section + generated --help snippet.
• toolr-command-authoring and toolr-ci-setup skills teach the new command (authoring for local test runs, CI for --no-sync deterministic runs).

Tests

• New crates/toolr/tests/project_venv_run.rs: missing-venv / stale errors, exit-code passthrough, arg pass-through via --, command-not-found nudge, --no-sync gating. The not-found nudge runs on all platforms; an ignored real-venv test covers real Scripts\*.exe PATHEXT resolution + exit-code passthrough on the Windows CI leg.
• Full mise run test and prek run --all-files green.

Design + plan archived under specs/archive/2026/.

[s0undt3ch]

This change is part of the following stack:

• feat(cli): add toolr project venv run #378 ◀

_{Change managed by git-spice.}

[codecov]

Codecov Report

❌ Patch coverage is 86.04651% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.8%. Comparing base (3fcf63d) to head (6c20439).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/toolr/src/project.rs	80.6%	12 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #378   +/-   ##
=====================================
  Coverage   93.8%   93.8%           
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  Files         96      96           
  Lines      15939   16023   +84     
  Branches     118     118           
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+ Hits       14958   15039   +81     
- Misses       971     974    +3     
  Partials      10      10           

Flag	Coverage Δ
3.11	93.8% <86.0%> (+<0.1%)	⬆️
3.12	93.8% <86.0%> (+<0.1%)	⬆️
3.13	93.8% <86.0%> (+<0.1%)	⬆️
3.14	93.8% <86.0%> (+<0.1%)	⬆️
macos-latest	93.8% <86.0%> (+<0.1%)	⬆️
ubuntu-latest	93.8% <86.0%> (+<0.1%)	⬆️
windows-latest	90.5% <80.2%> (+0.1%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
toolr-core	94.3% <ø> (+<0.1%)	⬆️
toolr	92.8% <86.0%> (+<0.1%)	⬆️
toolr-py	96.0% <ø> (ø)
xtask	90.3% <ø> (ø)

Files with missing lines	Coverage Δ
crates/toolr/src/builtin_completions.rs	99.5% <100.0%> (ø)
crates/toolr/src/cli.rs	94.5% <100.0%> (+0.1%)	⬆️
crates/toolr/src/project.rs	83.7% <80.6%> (+0.8%)	⬆️

... and 1 file with indirect coverage changes