ci: add rustfmt and clippy components explicitly

rustup auto-installs the pinned toolchain from rust-toolchain on the runner
but not its listed components; the fmt job failed with "cargo-fmt is not
installed for the toolchain". Add the component in the two jobs that need it.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CBgs2nSi4H2mdh8kD8vMX5

.gitea/workflows/ci.yml

@@ -24,14 +24,19 @@ concurrency:
 env:
   CARGO_INCREMENTAL: "0"
   CARGO_TERM_COLOR: always
-  # rust-toolchain pins 1.93.0; rustup on the runner installs it on first use.
-  RUSTUP_TOOLCHAIN: 1.93.0
+
+# rust-toolchain pins 1.93.0. rustup on the runner auto-installs the toolchain
+# on first use but NOT the components the file lists (observed: "cargo-fmt is
+# not installed for the toolchain"), so each job that needs one adds it
+# explicitly; the call is a no-op once present.
 
 jobs:
   fmt:
     runs-on: rust
     steps:
       - uses: actions/checkout@v4
+      - name: toolchain
+        run: rustup component add rustfmt
       - name: rustfmt
         run: cargo fmt --all -- --check
 
@@ -40,6 +45,8 @@ jobs:
     needs: fmt
     steps:
       - uses: actions/checkout@v4
+      - name: toolchain
+        run: rustup component add clippy
       - name: clippy (all targets, all features, warnings denied)
         # Same invocation as clippy.sh so local and CI agree.
         run: cargo clippy --workspace --all-targets --all-features --locked -- -D warnings