fix(ci): unbreak main's clippy, and let the tmux audit test the exemption

[Dygreens]

Two things, and the first is urgent: main is red and it's my fault.

1. clippy (deny warnings) fails on main as of f0be7a46 (my #107 merge)

warning: unnecessary use of `clone` to create a slice from a reference
    --> crates/amux-server/src/runtime_jobs/scheduler.rs:2306:45

One line: &[o.clone()] → std::slice::from_ref(&o).

Why it got through: I verified with cargo clippy -p amux-server --lib. CI runs cargo clippy --workspace --all-targets -- -D warnings. The lint is in a test, which --lib never compiles. I checked a narrower surface than the gate does and read the green as if it meant the same thing.

Verified here with CI's exact command rather than a convenient shorthand.

2. AEAB-23 — the planted-offender test re-implemented the scanner

offenders() and the_audit_detects_a_planted_non_exact_target held two copies of the same ~30-line loop, so the test could not observe a change to the real scanner.

Extracted scan(src) -> Vec<(usize, String)>, used by both. The exemption logic and its comment are 8db4326's, moved verbatim — a test-only refactor with no behaviour change.

The card overstated this, and I'm correcting it

I wrote that "NOTHING tests" the exemption. Not quite. every_tmux_target_uses_the_exact_match_helpers covers the narrow direction incidentally — remove the exemption and it fails, because email.rs really does contain a touch -t. That coverage is accidental (it evaporates the moment that unrelated file changes) but it isn't nothing.

The real hole is the other direction, and it's the one that matters. Measured, not argued — widen the exemption so it swallows tmux too (if matches!(name, Some(_n))):

	result
against main's tests	2 passed, 0 failed — guard fully disabled, CI green
against these tests	1 failed — caught

An exemption a shade too broad silences the guard while leaving main green, which is indistinguishable from the guard working. That's the expensive direction, and main could not see it.

So the_non_tmux_exemption_silences_touch_but_never_tmux asserts all three:

• touch -t is exempt — the false positive that failed CI
• a literal Command::new("tmux") is still flagged — or the fix deleted the guard
• a helper-invoked tmux target still audited — api/metrics.rs's real cmd_output("tmux", …) shape, where there's no literal program to attribute. This is the fail-safe case a broader exemption loses first.

Verification — CI's exact commands, all three

cargo check --workspace --all-targets            clean
cargo clippy --workspace --all-targets -D warnings   exit 0
cargo test --workspace                           39 result lines, 0 failed
tmux_target_audit                                3 passed

🤖 Generated with Claude Code

https://claude.ai/code/session_01B4vuEScunv4K6RMwQoT9xx