[thekevinbot]

Re-pins [rust.coverage] to the tree's actual coverage. The floors had drifted
2-7 points under, which is not a ratchet: a PR could delete a meaningful amount
of covered branch logic and the gate would stay green.

Fixes #1136

Measured on 59474c3 (current main) from packages/rust with
cargo +nightly llvm-cov --lib --features cli --branch. Fresh numbers, not the
ones in the issue body: #1146 and #1141 landed after those were taken, and
branch came out at 79.49 rather than 80.06.

dimension	old floor	measured actual	new floor	slack
lines	92	94.54	94	0.54
regions	91	93.67	93	0.67
functions	91	93.16	93	0.16
branch	72	79.49	79	0.49

Each floor is the highest integer strictly under its actual, per the rule the
file's own header states. No dimension was softened to buy slack. The in-file
comment records the fresh actuals and explains why the numbers moved up for
once: the recent refactors pulled pure logic out of the effectful modules the
unit tier cannot reach and into wholly unit-testable ones (extension_resolution.rs,
row_event_flat.rs, path_table.rs), which lifts the numerator and, for
branch, adds fully-covered branch regions to the denominator.

The sub-90 branch exception is unchanged in kind — 79 is still short of the

=90 ideal for the two documented reasons (effectful paths live in the
integration tier by design, #233; --branch instruments #[cfg(test)]
modules). This just stops leaving seven points unguarded.

Fragility is reintroduced deliberately: with under a
point of slack everywhere, a PR that merely adds well-formed unit tests can
lower branch and trip the floor, and the fix then is to nudge that floor down
to the new actual.

No test added, deleted, or weakened. [python.coverage], [e2e], and
[rust].features untouched.

Verification

npx testing-conventions unit coverage --language rust cannot run locally — it
resolves the stable toolchain regardless of RUSTUP_TOOLCHAIN, and --branch
needs nightly. just preflight does not cover this gate either (it is the
bespoke Rust unit coverage floor job in dirsql-rust-ci.yml), so CI on this
PR is the real verification. just preflight was run anyway on the committed
diff: 0 failing pair(s), 3 skipped.

E2E Verification

N/A - CI/config only

Changelog / Migrations

• Not required — config-only, no shipped behavior change (skip-changelog on the commit)
• Migration fragment not required — no public API or runtime behavior change