grcov, cargo-mutants, llvm-tools, and astral-sh/setup-uv were left over
from the coverage and mutation steps disabled in b33250f. Installing
them on every run added several minutes and a transient failure surface
without exercising anything. The leading comment now records what to
restore when those steps come back.

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index cddc300..efc4202 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -21,12 +21,13 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           persist-credentials: false
-      - run: rustup component add clippy rustfmt llvm-tools
-      - run: cargo install grcov cargo-mutants just
-      - uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
+      - run: rustup component add clippy rustfmt
+      - run: cargo install just
       - run: cargo fmt --check
       - run: just clippy test
       # Coverage and mutation testing disabled during early exploratory work.
+      # When re-enabling: add llvm-tools component, install grcov + cargo-mutants,
+      # add astral-sh/setup-uv, and uncomment the recipes below.
       # - run: just coverage
       # - run: just mutants